Mithril 2 update (#2255)

* Update frontend to Mithril 2

- Update Mithril version to v2.0.4
- Add Typescript typings for Mithril
- Rename "props" to "attrs"; "initProps" to "initAttrs"; "m.prop" to "m.stream"; "m.withAttr" to "utils/withAttr".
- Use Mithril 2's new lifecycle hooks
- SubtreeRetainer has been rewritten to be more useful for the new system
- Utils for forcing page re-initializations have been added (force attr in links, setRouteWithForcedRefresh util)
- Other mechanical changes, following the upgrade guide
- Remove some of the custom stuff in our Component base class
- Introduce "fragments" for non-components that control their own DOM
- Remove Mithril patches, introduce a few new ones (route attrs in <a>; 
- Redesign AlertManagerState `show` with 3 overloads: `show(children)`, `show(attrs, children)`, `show(componentClass, attrs, children)`
- The `affixedSidebar` util has been replaced with an `AffixedSidebar` component

Challenges:
- `children` and `tag` are now reserved, and can not be used as attr names
- Behavior of links to current page changed in Mithril. If moving to a page that is handled by the same component, the page component WILL NOT be re-initialized by default. Additional code to keep track of the current url is needed (See IndexPage, DiscussionPage, and UserPage for examples)
- Native Promise rejections are shown on console when not handled
- Instances of components can no longer be stored. The state pattern should be used instead.

Refs #1821.

Co-authored-by: Alexander Skvortsov <sasha.skvortsov109@gmail.com>
Co-authored-by: Matthew Kilgore <tankerkiller125@gmail.com>
Co-authored-by: Franz Liedke <franz@develophp.org>

js/package-lock.json

@@ -1075,6 +1075,11 @@
       "integrity": "sha512-rr+OQyAjxze7GgWrSaJwydHStIhHq2lvY3BOC2Mj7KnzI7XK0Uw1TOOdI9lDoajEbSWLiYgoo4f1R51erQfhPQ==",
       "dev": true
     },
+    "@types/mithril": {
+      "version": "2.0.3",
+      "resolved": "https://registry.npmjs.org/@types/mithril/-/mithril-2.0.3.tgz",
+      "integrity": "sha512-cZHOdO2IiXYeyjeDYdbOisSdfaJRzfmRo3zVzgu33IWTMA0KEQObp9fdvqcuYdPz93iJ1yCl19GcEjo/9yv+yA=="
+    },
     "@types/parse-json": {
       "version": "4.0.0",
       "resolved": "https://registry.npmjs.org/@types/parse-json/-/parse-json-4.0.0.tgz",
@@ -3807,9 +3812,9 @@
       }
     },
     "mithril": {
-      "version": "0.2.8",
-      "resolved": "https://registry.npmjs.org/mithril/-/mithril-0.2.8.tgz",
-      "integrity": "sha512-9XuGnVmS2OyFexUuP/CcJFFJjHLM+RGYBxyVRNyQ6khbMfDJIF/xyZ4zq18ZRfPagpFmWUFpjHd5ZqPULGZyNg=="
+      "version": "2.0.4",
+      "resolved": "https://registry.npmjs.org/mithril/-/mithril-2.0.4.tgz",
+      "integrity": "sha512-mgw+DMZlhMS4PpprF6dl7ZoeZq5GGcAuWnrg5e12MvaGauc4jzWsDZtVGRCktsiQczOEUr2K5teKbE5k44RlOg=="
     },
     "mixin-deep": {
       "version": "1.3.2",

js/package.json

@@ -3,6 +3,7 @@
   "name": "@flarum/core",
   "dependencies": {
     "@babel/preset-typescript": "^7.10.1",
+    "@types/mithril": "^2.0.3",
     "bootstrap": "^3.4.1",
     "classnames": "^2.2.5",
     "color-thief-browser": "^2.0.2",
@@ -13,7 +14,7 @@
     "jquery.hotkeys": "^0.1.0",
     "lodash-es": "^4.17.14",
     "m.attrs.bidi": "github:tobscure/m.attrs.bidi",
-    "mithril": "^0.2.8",
+    "mithril": "^2.0.4",
     "punycode": "^2.1.1",
     "spin.js": "^3.1.0",
     "webpack": "^4.43.0",

js/shims.d.ts

@@ -0,0 +1,48 @@
+// Mithril
+import * as Mithril from 'mithril';
+import Stream from 'mithril/stream';
+
+// Other third-party libs
+import * as _dayjs from 'dayjs';
+import * as _$ from 'jquery';
+
+// Globals from flarum/core
+import Application from './src/common/Application';
+
+/**
+ * Helpers that flarum/core patches into Mithril
+ */
+interface m extends Mithril.Static {
+  prop: typeof Stream;
+}
+
+/**
+ * Export Mithril typings globally.
+ *
+ * This lets us use these typings without an extra import everywhere we use
+ * Mithril in a TypeScript file.
+ */
+export as namespace Mithril;
+
+/**
+ * flarum/core exposes several extensions globally:
+ *
+ * - jQuery for convenient DOM manipulation
+ * - Mithril for VDOM and components
+ * - dayjs for date/time operations
+ *
+ * Since these are already part of the global namespace, extensions won't need
+ * to (and should not) bundle these themselves.
+ */
+declare global {
+  const $: typeof _$;
+  const m: m;
+  const dayjs: typeof _dayjs;
+}
+
+/**
+ * All global variables owned by flarum/core.
+ */
+declare global {
+  const app: Application;
+}

js/src/admin/AdminApplication.js

@@ -27,13 +27,18 @@ export default class AdminApplication extends Application {
    * @inheritdoc
    */
   mount() {
-    m.mount(document.getElementById('app-navigation'), Navigation.component({ className: 'App-backControl', drawer: true }));
-    m.mount(document.getElementById('header-navigation'), Navigation.component());
-    m.mount(document.getElementById('header-primary'), HeaderPrimary.component());
-    m.mount(document.getElementById('header-secondary'), HeaderSecondary.component());
-    m.mount(document.getElementById('admin-navigation'), AdminNav.component());
+    m.mount(document.getElementById('app-navigation'), { view: () => Navigation.component({ className: 'App-backControl', drawer: true }) });
+    m.mount(document.getElementById('header-navigation'), Navigation);
+    m.mount(document.getElementById('header-primary'), HeaderPrimary);
+    m.mount(document.getElementById('header-secondary'), HeaderSecondary);
+    m.mount(document.getElementById('admin-navigation'), AdminNav);
+
+    // Mithril does not render the home route on https://example.com/admin, so
+    // we need to go to https://example.com/admin#/ explicitly.
+    if (!document.location.hash) document.location.hash = '#/';
+
+    m.route.prefix = '#';
 
-    m.route.mode = 'hash';
     super.mount();
 
     // If an extension has just been enabled, then we will run its settings

js/src/admin/components/AdminLinkButton.js

@@ -10,11 +10,7 @@
 import LinkButton from '../../common/components/LinkButton';
 
 export default class AdminLinkButton extends LinkButton {
-  getButtonContent() {
-    const content = super.getButtonContent();
-
-    content.push(<div className="AdminLinkButton-description">{this.props.description}</div>);
-
-    return content;
+  getButtonContent(children) {
+    return [...super.getButtonContent(children), <div className="AdminLinkButton-description">{this.attrs.description}</div>];
   }
 }

js/src/admin/components/AdminNav.js

@@ -31,62 +31,74 @@ export default class AdminNav extends Component {
 
     items.add(
       'dashboard',
-      AdminLinkButton.component({
+      AdminLinkButton.component(
+        {
           href: app.route('dashboard'),
           icon: 'far fa-chart-bar',
-        children: app.translator.trans('core.admin.nav.dashboard_button'),
           description: app.translator.trans('core.admin.nav.dashboard_text'),
-      })
+        },
+        app.translator.trans('core.admin.nav.dashboard_button')
+      )
     );
 
     items.add(
       'basics',
-      AdminLinkButton.component({
+      AdminLinkButton.component(
+        {
           href: app.route('basics'),
           icon: 'fas fa-pencil-alt',
-        children: app.translator.trans('core.admin.nav.basics_button'),
           description: app.translator.trans('core.admin.nav.basics_text'),
-      })
+        },
+        app.translator.trans('core.admin.nav.basics_button')
+      )
     );
 
     items.add(
       'mail',
-      AdminLinkButton.component({
+      AdminLinkButton.component(
+        {
           href: app.route('mail'),
           icon: 'fas fa-envelope',
-        children: app.translator.trans('core.admin.nav.email_button'),
           description: app.translator.trans('core.admin.nav.email_text'),
-      })
+        },
+        app.translator.trans('core.admin.nav.email_button')
+      )
     );
 
     items.add(
       'permissions',
-      AdminLinkButton.component({
+      AdminLinkButton.component(
+        {
           href: app.route('permissions'),
           icon: 'fas fa-key',
-        children: app.translator.trans('core.admin.nav.permissions_button'),
           description: app.translator.trans('core.admin.nav.permissions_text'),
-      })
+        },
+        app.translator.trans('core.admin.nav.permissions_button')
+      )
     );
 
     items.add(
       'appearance',
-      AdminLinkButton.component({
+      AdminLinkButton.component(
+        {
           href: app.route('appearance'),
           icon: 'fas fa-paint-brush',
-        children: app.translator.trans('core.admin.nav.appearance_button'),
           description: app.translator.trans('core.admin.nav.appearance_text'),
-      })
+        },
+        app.translator.trans('core.admin.nav.appearance_button')
+      )
     );
 
     items.add(
       'extensions',
-      AdminLinkButton.component({
+      AdminLinkButton.component(
+        {
           href: app.route('extensions'),
           icon: 'fas fa-puzzle-piece',
-        children: app.translator.trans('core.admin.nav.extensions_button'),
           description: app.translator.trans('core.admin.nav.extensions_text'),
-      })
+        },
+        app.translator.trans('core.admin.nav.extensions_button')
+      )
     );
 
     return items;

js/src/admin/components/AppearancePage.js

@@ -6,15 +6,16 @@ import EditCustomHeaderModal from './EditCustomHeaderModal';
 import EditCustomFooterModal from './EditCustomFooterModal';
 import UploadImageButton from './UploadImageButton';
 import saveSettings from '../utils/saveSettings';
+import withAttr from '../../common/utils/withAttr';
 
 export default class AppearancePage extends Page {
-  init() {
-    super.init();
+  oninit(vnode) {
+    super.oninit(vnode);
 
-    this.primaryColor = m.prop(app.data.settings.theme_primary_color);
-    this.secondaryColor = m.prop(app.data.settings.theme_secondary_color);
-    this.darkMode = m.prop(app.data.settings.theme_dark_mode);
-    this.coloredHeader = m.prop(app.data.settings.theme_colored_header);
+    this.primaryColor = m.stream(app.data.settings.theme_primary_color);
+    this.secondaryColor = m.stream(app.data.settings.theme_secondary_color);
+    this.darkMode = m.stream(app.data.settings.theme_dark_mode);
+    this.coloredHeader = m.stream(app.data.settings.theme_colored_header);
   }
 
   view() {
@@ -27,40 +28,34 @@ export default class AppearancePage extends Page {
               <div className="helpText">{app.translator.trans('core.admin.appearance.colors_text')}</div>
 
               <div className="AppearancePage-colors-input">
-                <input
-                  className="FormControl"
-                  type="text"
-                  placeholder="#aaaaaa"
-                  value={this.primaryColor()}
-                  onchange={m.withAttr('value', this.primaryColor)}
-                />
-                <input
-                  className="FormControl"
-                  type="text"
-                  placeholder="#aaaaaa"
-                  value={this.secondaryColor()}
-                  onchange={m.withAttr('value', this.secondaryColor)}
-                />
+                <input className="FormControl" type="text" placeholder="#aaaaaa" bidi={this.primaryColor} />
+                <input className="FormControl" type="text" placeholder="#aaaaaa" bidi={this.secondaryColor} />
               </div>
 
-              {Switch.component({
+              {Switch.component(
+                {
                   state: this.darkMode(),
-                children: app.translator.trans('core.admin.appearance.dark_mode_label'),
                   onchange: this.darkMode,
-              })}
+                },
+                app.translator.trans('core.admin.appearance.dark_mode_label')
+              )}
 
-              {Switch.component({
+              {Switch.component(
+                {
                   state: this.coloredHeader(),
-                children: app.translator.trans('core.admin.appearance.colored_header_label'),
                   onchange: this.coloredHeader,
-              })}
+                },
+                app.translator.trans('core.admin.appearance.colored_header_label')
+              )}
 
-              {Button.component({
+              {Button.component(
+                {
                   className: 'Button Button--primary',
                   type: 'submit',
-                children: app.translator.trans('core.admin.appearance.submit_button'),
                   loading: this.loading,
-              })}
+                },
+                app.translator.trans('core.admin.appearance.submit_button')
+              )}
             </fieldset>
           </form>
 
@@ -79,31 +74,37 @@ export default class AppearancePage extends Page {
           <fieldset>
             <legend>{app.translator.trans('core.admin.appearance.custom_header_heading')}</legend>
             <div className="helpText">{app.translator.trans('core.admin.appearance.custom_header_text')}</div>
-            {Button.component({
+            {Button.component(
+              {
                 className: 'Button',
-              children: app.translator.trans('core.admin.appearance.edit_header_button'),
                 onclick: () => app.modal.show(EditCustomHeaderModal),
-            })}
+              },
+              app.translator.trans('core.admin.appearance.edit_header_button')
+            )}
           </fieldset>
 
           <fieldset>
             <legend>{app.translator.trans('core.admin.appearance.custom_footer_heading')}</legend>
             <div className="helpText">{app.translator.trans('core.admin.appearance.custom_footer_text')}</div>
-            {Button.component({
+            {Button.component(
+              {
                 className: 'Button',
-              children: app.translator.trans('core.admin.appearance.edit_footer_button'),
                 onclick: () => app.modal.show(EditCustomFooterModal),
-            })}
+              },
+              app.translator.trans('core.admin.appearance.edit_footer_button')
+            )}
           </fieldset>
 
           <fieldset>
             <legend>{app.translator.trans('core.admin.appearance.custom_styles_heading')}</legend>
             <div className="helpText">{app.translator.trans('core.admin.appearance.custom_styles_text')}</div>
-            {Button.component({
+            {Button.component(
+              {
                 className: 'Button',
-              children: app.translator.trans('core.admin.appearance.edit_css_button'),
                 onclick: () => app.modal.show(EditCustomCssModal),
-            })}
+              },
+              app.translator.trans('core.admin.appearance.edit_css_button')
+            )}
           </fieldset>
         </div>
       </div>

js/src/admin/components/BasicsPage.js

@@ -5,10 +5,11 @@ import Button from '../../common/components/Button';
 import saveSettings from '../utils/saveSettings';
 import ItemList from '../../common/utils/ItemList';
 import Switch from '../../common/components/Switch';
+import withAttr from '../../common/utils/withAttr';
 
 export default class BasicsPage extends Page {
-  init() {
-    super.init();
+  oninit(vnode) {
+    super.oninit(vnode);
 
     this.loading = false;
 
@@ -25,7 +26,7 @@ export default class BasicsPage extends Page {
     this.values = {};
 
     const settings = app.data.settings;
-    this.fields.forEach((key) => (this.values[key] = m.prop(settings[key])));
+    this.fields.forEach((key) => (this.values[key] = m.stream(settings[key])));
 
     this.localeOptions = {};
     const locales = app.data.locales;
@@ -49,45 +50,51 @@ export default class BasicsPage extends Page {
       <div className="BasicsPage">
         <div className="container">
           <form onsubmit={this.onsubmit.bind(this)}>
-            {FieldSet.component({
+            {FieldSet.component(
+              {
                 label: app.translator.trans('core.admin.basics.forum_title_heading'),
-              children: [<input className="FormControl" value={this.values.forum_title()} oninput={m.withAttr('value', this.values.forum_title)} />],
-            })}
+              },
+              [<input className="FormControl" bidi={this.values.forum_title} />]
+            )}
 
-            {FieldSet.component({
+            {FieldSet.component(
+              {
                 label: app.translator.trans('core.admin.basics.forum_description_heading'),
-              children: [
+              },
+              [
                 <div className="helpText">{app.translator.trans('core.admin.basics.forum_description_text')}</div>,
-                <textarea
-                  className="FormControl"
-                  value={this.values.forum_description()}
-                  oninput={m.withAttr('value', this.values.forum_description)}
-                />,
-              ],
-            })}
+                <textarea className="FormControl" bidi={this.values.forum_description} />,
+              ]
+            )}
 
             {Object.keys(this.localeOptions).length > 1
-              ? FieldSet.component({
+              ? FieldSet.component(
+                  {
                     label: app.translator.trans('core.admin.basics.default_language_heading'),
-                  children: [
+                  },
+                  [
                     Select.component({
                       options: this.localeOptions,
                       value: this.values.default_locale(),
                       onchange: this.values.default_locale,
                     }),
-                    Switch.component({
+                    Switch.component(
+                      {
                         state: this.values.show_language_selector(),
                         onchange: this.values.show_language_selector,
-                      children: app.translator.trans('core.admin.basics.show_language_selector_label'),
-                    }),
-                  ],
-                })
+                      },
+                      app.translator.trans('core.admin.basics.show_language_selector_label')
+                    ),
+                  ]
+                )
               : ''}
 
-            {FieldSet.component({
+            {FieldSet.component(
+              {
                 label: app.translator.trans('core.admin.basics.home_page_heading'),
                 className: 'BasicsPage-homePage',
-              children: [
+              },
+              [
                 <div className="helpText">{app.translator.trans('core.admin.basics.home_page_text')}</div>,
                 this.homePageItems()
                   .toArray()
@@ -98,51 +105,52 @@ export default class BasicsPage extends Page {
                         name="homePage"
                         value={path}
                         checked={this.values.default_route() === path}
-                        onclick={m.withAttr('value', this.values.default_route)}
+                        onclick={withAttr('value', this.values.default_route)}
                       />
                       {label}
                     </label>
                   )),
-              ],
-            })}
+              ]
+            )}
 
-            {FieldSet.component({
+            {FieldSet.component(
+              {
                 label: app.translator.trans('core.admin.basics.welcome_banner_heading'),
                 className: 'BasicsPage-welcomeBanner',
-              children: [
+              },
+              [
                 <div className="helpText">{app.translator.trans('core.admin.basics.welcome_banner_text')}</div>,
                 <div className="BasicsPage-welcomeBanner-input">
-                  <input className="FormControl" value={this.values.welcome_title()} oninput={m.withAttr('value', this.values.welcome_title)} />
-                  <textarea
-                    className="FormControl"
-                    value={this.values.welcome_message()}
-                    oninput={m.withAttr('value', this.values.welcome_message)}
-                  />
+                  <input className="FormControl" bidi={this.values.welcome_title} />
+                  <textarea className="FormControl" bidi={this.values.welcome_message} />
                 </div>,
-              ],
-            })}
+              ]
+            )}
 
             {Object.keys(this.displayNameOptions).length > 1
-              ? FieldSet.component({
+              ? FieldSet.component(
+                  {
                     label: app.translator.trans('core.admin.basics.display_name_heading'),
-                  children: [
+                  },
+                  [
                     <div className="helpText">{app.translator.trans('core.admin.basics.display_name_text')}</div>,
                     Select.component({
                       options: this.displayNameOptions,
-                      value: this.values.display_name_driver(),
-                      onchange: this.values.display_name_driver,
+                      bidi: this.values.display_name_driver,
                     }),
-                  ],
-                })
+                  ]
+                )
               : ''}
 
-            {Button.component({
+            {Button.component(
+              {
                 type: 'submit',
                 className: 'Button Button--primary',
-              children: app.translator.trans('core.admin.basics.submit_button'),
                 loading: this.loading,
                 disabled: !this.changed(),
-            })}
+              },
+              app.translator.trans('core.admin.basics.submit_button')
+            )}
           </form>
         </div>
       </div>
@@ -185,10 +193,7 @@ export default class BasicsPage extends Page {
 
     saveSettings(settings)
       .then(() => {
-        this.successAlert = app.alerts.show({
-          type: 'success',
-          children: app.translator.trans('core.admin.basics.saved_message'),
-        });
+        this.successAlert = app.alerts.show({ type: 'success' }, app.translator.trans('core.admin.basics.saved_message'));
       })
       .catch(() => {})
       .then(() => {

js/src/admin/components/EditGroupModal.js

@@ -4,20 +4,23 @@ import Badge from '../../common/components/Badge';
 import Group from '../../common/models/Group';
 import ItemList from '../../common/utils/ItemList';
 import Switch from '../../common/components/Switch';
+import withAttr from '../../common/utils/withAttr';
 
 /**
  * The `EditGroupModal` component shows a modal dialog which allows the user
  * to create or edit a group.
  */
 export default class EditGroupModal extends Modal {
-  init() {
-    this.group = this.props.group || app.store.createRecord('groups');
+  oninit(vnode) {
+    super.oninit(vnode);
 
-    this.nameSingular = m.prop(this.group.nameSingular() || '');
-    this.namePlural = m.prop(this.group.namePlural() || '');
-    this.icon = m.prop(this.group.icon() || '');
-    this.color = m.prop(this.group.color() || '');
-    this.isHidden = m.prop(this.group.isHidden() || false);
+    this.group = this.attrs.group || app.store.createRecord('groups');
+
+    this.nameSingular = m.stream(this.group.nameSingular() || '');
+    this.namePlural = m.stream(this.group.namePlural() || '');
+    this.icon = m.stream(this.group.icon() || '');
+    this.color = m.stream(this.group.color() || '');
+    this.isHidden = m.stream(this.group.isHidden() || false);
   }
 
   className() {
@@ -53,18 +56,8 @@ export default class EditGroupModal extends Modal {
       <div className="Form-group">
         <label>{app.translator.trans('core.admin.edit_group.name_label')}</label>
         <div className="EditGroupModal-name-input">
-          <input
-            className="FormControl"
-            placeholder={app.translator.trans('core.admin.edit_group.singular_placeholder')}
-            value={this.nameSingular()}
-            oninput={m.withAttr('value', this.nameSingular)}
-          />
-          <input
-            className="FormControl"
-            placeholder={app.translator.trans('core.admin.edit_group.plural_placeholder')}
-            value={this.namePlural()}
-            oninput={m.withAttr('value', this.namePlural)}
-          />
+          <input className="FormControl" placeholder={app.translator.trans('core.admin.edit_group.singular_placeholder')} bidi={this.nameSingular} />
+          <input className="FormControl" placeholder={app.translator.trans('core.admin.edit_group.plural_placeholder')} bidi={this.namePlural} />
         </div>
       </div>,
       30
@@ -74,7 +67,7 @@ export default class EditGroupModal extends Modal {
       'color',
       <div className="Form-group">
         <label>{app.translator.trans('core.admin.edit_group.color_label')}</label>
-        <input className="FormControl" placeholder="#aaaaaa" value={this.color()} oninput={m.withAttr('value', this.color)} />
+        <input className="FormControl" placeholder="#aaaaaa" bidi={this.color} />
       </div>,
       20
     );
@@ -86,7 +79,7 @@ export default class EditGroupModal extends Modal {
         <div className="helpText">
           {app.translator.trans('core.admin.edit_group.icon_text', { a: <a href="https://fontawesome.com/icons?m=free" tabindex="-1" /> })}
         </div>
-        <input className="FormControl" placeholder="fas fa-bolt" value={this.icon()} oninput={m.withAttr('value', this.icon)} />
+        <input className="FormControl" placeholder="fas fa-bolt" bidi={this.icon} />
       </div>,
       10
     );
@@ -94,11 +87,13 @@ export default class EditGroupModal extends Modal {
     items.add(
       'hidden',
       <div className="Form-group">
-        {Switch.component({
+        {Switch.component(
+          {
             state: !!Number(this.isHidden()),
-          children: app.translator.trans('core.admin.edit_group.hide_label'),
             onchange: this.isHidden,
-        })}
+          },
+          app.translator.trans('core.admin.edit_group.hide_label')
+        )}
       </div>,
       10
     );
@@ -106,12 +101,14 @@ export default class EditGroupModal extends Modal {
     items.add(
       'submit',
       <div className="Form-group">
-        {Button.component({
+        {Button.component(
+          {
             type: 'submit',
             className: 'Button Button--primary EditGroupModal-save',
             loading: this.loading,
-          children: app.translator.trans('core.admin.edit_group.submit_button'),
-        })}
+          },
+          app.translator.trans('core.admin.edit_group.submit_button')
+        )}
         {this.group.exists && this.group.id() !== Group.ADMINISTRATOR_ID ? (
           <button type="button" className="Button EditGroupModal-delete" onclick={this.deleteGroup.bind(this)}>
             {app.translator.trans('core.admin.edit_group.delete_button')}

js/src/admin/components/ExtensionsPage.js

@@ -12,12 +12,14 @@ export default class ExtensionsPage extends Page {
       <div className="ExtensionsPage">
         <div className="ExtensionsPage-header">
           <div className="container">
-            {Button.component({
-              children: app.translator.trans('core.admin.extensions.add_button'),
+            {Button.component(
+              {
                 icon: 'fas fa-plus',
                 className: 'Button Button--primary',
                 onclick: () => app.modal.show(AddExtensionModal),
-            })}
+              },
+              app.translator.trans('core.admin.extensions.add_button')
+            )}
           </div>
         </div>
 
@@ -72,20 +74,22 @@ export default class ExtensionsPage extends Page {
     if (app.extensionSettings[name]) {
       items.add(
         'settings',
-        Button.component({
+        Button.component(
+          {
             icon: 'fas fa-cog',
-          children: app.translator.trans('core.admin.extensions.settings_button'),
             onclick: app.extensionSettings[name],
-        })
+          },
+          app.translator.trans('core.admin.extensions.settings_button')
+        )
       );
     }
 
     if (!enabled) {
       items.add(
         'uninstall',
-        Button.component({
+        Button.component(
+          {
             icon: 'far fa-trash-alt',
-          children: app.translator.trans('core.admin.extensions.uninstall_button'),
             onclick: () => {
               app
                 .request({
@@ -96,7 +100,9 @@ export default class ExtensionsPage extends Page {
 
               app.modal.show(LoadingModal);
             },
-        })
+          },
+          app.translator.trans('core.admin.extensions.uninstall_button')
+        )
       );
     }
 
@@ -116,7 +122,7 @@ export default class ExtensionsPage extends Page {
       .request({
         url: app.forum.attribute('apiUrl') + '/extensions/' + id,
         method: 'PATCH',
-        data: { enabled: !enabled },
+        body: { enabled: !enabled },
       })
       .then(() => {
         if (!enabled) localStorage.setItem('enabledExtension', id);

js/src/admin/components/HeaderSecondary.js

@@ -11,13 +11,6 @@ export default class HeaderSecondary extends Component {
     return <ul className="Header-controls">{listItems(this.items().toArray())}</ul>;
   }
 
-  config(isInitialized, context) {
-    // Since this component is 'above' the content of the page (that is, it is a
-    // part of the global UI that persists between routes), we will flag the DOM
-    // to be retained across route changes.
-    context.retain = true;
-  }
-
   /**
    * Build an item list for the controls.
    *

js/src/admin/components/MailPage.js

@@ -5,10 +5,11 @@ import Alert from '../../common/components/Alert';
 import Select from '../../common/components/Select';
 import LoadingIndicator from '../../common/components/LoadingIndicator';
 import saveSettings from '../utils/saveSettings';
+import withAttr from '../../common/utils/withAttr';
 
 export default class MailPage extends Page {
-  init() {
-    super.init();
+  oninit(vnode) {
+    super.oninit(vnode);
 
     this.saving = false;
     this.sendingTest = false;
@@ -24,7 +25,7 @@ export default class MailPage extends Page {
     this.status = { sending: false, errors: {} };
 
     const settings = app.data.settings;
-    this.fields.forEach((key) => (this.values[key] = m.prop(settings[key])));
+    this.fields.forEach((key) => (this.values[key] = m.stream(settings[key])));
 
     app
       .request({
@@ -39,7 +40,7 @@ export default class MailPage extends Page {
         for (const driver in this.driverFields) {
           for (const field in this.driverFields[driver]) {
             this.fields.push(field);
-            this.values[field] = m.prop(settings[field]);
+            this.values[field] = m.stream(settings[field]);
           }
         }
 
@@ -69,23 +70,27 @@ export default class MailPage extends Page {
             <h2>{app.translator.trans('core.admin.email.heading')}</h2>
             <div className="helpText">{app.translator.trans('core.admin.email.text')}</div>
 
-            {FieldSet.component({
+            {FieldSet.component(
+              {
                 label: app.translator.trans('core.admin.email.addresses_heading'),
                 className: 'MailPage-MailSettings',
-              children: [
+              },
+              [
                 <div className="MailPage-MailSettings-input">
                   <label>
                     {app.translator.trans('core.admin.email.from_label')}
-                    <input className="FormControl" value={this.values.mail_from() || ''} oninput={m.withAttr('value', this.values.mail_from)} />
+                    <input className="FormControl" bidi={this.values.mail_from} />
                   </label>
                 </div>,
-              ],
-            })}
+              ]
+            )}
 
-            {FieldSet.component({
+            {FieldSet.component(
+              {
                 label: app.translator.trans('core.admin.email.driver_heading'),
                 className: 'MailPage-MailSettings',
-              children: [
+              },
+              [
                 <div className="MailPage-MailSettings-input">
                   <label>
                     {app.translator.trans('core.admin.email.driver_label')}
@@ -96,20 +101,24 @@ export default class MailPage extends Page {
                     />
                   </label>
                 </div>,
-              ],
-            })}
+              ]
+            )}
 
             {this.status.sending ||
-              Alert.component({
-                children: app.translator.trans('core.admin.email.not_sending_message'),
+              Alert.component(
+                {
                   dismissible: false,
-              })}
+                },
+                app.translator.trans('core.admin.email.not_sending_message')
+              )}
 
             {fieldKeys.length > 0 &&
-              FieldSet.component({
+              FieldSet.component(
+                {
                   label: app.translator.trans(`core.admin.email.${this.values.mail_driver()}_heading`),
                   className: 'MailPage-MailSettings',
-                children: [
+                },
+                [
                   <div className="MailPage-MailSettings-input">
                     {fieldKeys.map((field) => [
                       <label>
@@ -119,31 +128,37 @@ export default class MailPage extends Page {
                       this.status.errors[field] && <p className="ValidationError">{this.status.errors[field]}</p>,
                     ])}
                   </div>,
-                ],
-              })}
+                ]
+              )}
 
             <FieldSet>
-              {Button.component({
+              {Button.component(
+                {
                   type: 'submit',
                   className: 'Button Button--primary',
-                children: app.translator.trans('core.admin.email.submit_button'),
                   disabled: !this.changed(),
-              })}
+                },
+                app.translator.trans('core.admin.email.submit_button')
+              )}
             </FieldSet>
 
-            {FieldSet.component({
+            {FieldSet.component(
+              {
                 label: app.translator.trans('core.admin.email.send_test_mail_heading'),
                 className: 'MailPage-MailSettings',
-              children: [
+              },
+              [
                 <div className="helpText">{app.translator.trans('core.admin.email.send_test_mail_text', { email: app.session.user.email() })}</div>,
-                Button.component({
+                Button.component(
+                  {
                     className: 'Button Button--primary',
-                  children: app.translator.trans('core.admin.email.send_test_mail_button'),
                     disabled: this.sendingTest || this.changed(),
                     onclick: () => this.sendTestEmail(),
-                }),
-              ],
-            })}
+                  },
+                  app.translator.trans('core.admin.email.send_test_mail_button')
+                ),
+              ]
+            )}
           </form>
         </div>
       </div>
@@ -156,7 +171,7 @@ export default class MailPage extends Page {
     const prop = this.values[name];
 
     if (typeof field === 'string') {
-      return <input className="FormControl" value={prop() || ''} oninput={m.withAttr('value', prop)} />;
+      return <input className="FormControl" bidi={prop} />;
     } else {
       return <Select value={prop()} options={field} onchange={prop} />;
     }
@@ -179,10 +194,7 @@ export default class MailPage extends Page {
       })
       .then((response) => {
         this.sendingTest = false;
-        this.testEmailSuccessAlert = app.alerts.show({
-          type: 'success',
-          children: app.translator.trans('core.admin.email.send_test_mail_success'),
-        });
+        this.testEmailSuccessAlert = app.alerts.show({ type: 'success' }, app.translator.trans('core.admin.email.send_test_mail_success'));
       })
       .catch((error) => {
         this.sendingTest = false;
@@ -205,10 +217,7 @@ export default class MailPage extends Page {
 
     saveSettings(settings)
       .then(() => {
-        this.successAlert = app.alerts.show({
-          type: 'success',
-          children: app.translator.trans('core.admin.basics.saved_message'),
-        });
+        this.successAlert = app.alerts.show({ type: 'success' }, app.translator.trans('core.admin.basics.saved_message'));
       })
       .catch(() => {})
       .then(() => {

js/src/admin/components/PermissionDropdown.js

@@ -32,101 +32,109 @@ function filterByRequiredPermissions(groupIds, permission) {
 }
 
 export default class PermissionDropdown extends Dropdown {
-  static initProps(props) {
-    super.initProps(props);
+  static initAttrs(attrs) {
+    super.initAttrs(attrs);
 
-    props.className = 'PermissionDropdown';
-    props.buttonClassName = 'Button Button--text';
+    attrs.className = 'PermissionDropdown';
+    attrs.buttonClassName = 'Button Button--text';
   }
 
-  view() {
-    this.props.children = [];
+  view(vnode) {
+    const children = [];
 
-    let groupIds = app.data.permissions[this.props.permission] || [];
+    let groupIds = app.data.permissions[this.attrs.permission] || [];
 
-    groupIds = filterByRequiredPermissions(groupIds, this.props.permission);
+    groupIds = filterByRequiredPermissions(groupIds, this.attrs.permission);
 
     const everyone = groupIds.indexOf(Group.GUEST_ID) !== -1;
     const members = groupIds.indexOf(Group.MEMBER_ID) !== -1;
     const adminGroup = app.store.getById('groups', Group.ADMINISTRATOR_ID);
 
     if (everyone) {
-      this.props.label = Badge.component({ icon: 'fas fa-globe' });
+      this.attrs.label = Badge.component({ icon: 'fas fa-globe' });
     } else if (members) {
-      this.props.label = Badge.component({ icon: 'fas fa-user' });
+      this.attrs.label = Badge.component({ icon: 'fas fa-user' });
     } else {
-      this.props.label = [badgeForId(Group.ADMINISTRATOR_ID), groupIds.map(badgeForId)];
+      this.attrs.label = [badgeForId(Group.ADMINISTRATOR_ID), groupIds.map(badgeForId)];
     }
 
     if (this.showing) {
-      if (this.props.allowGuest) {
-        this.props.children.push(
-          Button.component({
-            children: [Badge.component({ icon: 'fas fa-globe' }), ' ', app.translator.trans('core.admin.permissions_controls.everyone_button')],
+      if (this.attrs.allowGuest) {
+        children.push(
+          Button.component(
+            {
               icon: everyone ? 'fas fa-check' : true,
               onclick: () => this.save([Group.GUEST_ID]),
               disabled: this.isGroupDisabled(Group.GUEST_ID),
-          })
+            },
+            [Badge.component({ icon: 'fas fa-globe' }), ' ', app.translator.trans('core.admin.permissions_controls.everyone_button')]
+          )
         );
       }
 
-      this.props.children.push(
-        Button.component({
-          children: [Badge.component({ icon: 'fas fa-user' }), ' ', app.translator.trans('core.admin.permissions_controls.members_button')],
+      children.push(
+        Button.component(
+          {
             icon: members ? 'fas fa-check' : true,
             onclick: () => this.save([Group.MEMBER_ID]),
             disabled: this.isGroupDisabled(Group.MEMBER_ID),
-        }),
+          },
+          [Badge.component({ icon: 'fas fa-user' }), ' ', app.translator.trans('core.admin.permissions_controls.members_button')]
+        ),
 
         Separator.component(),
 
-        Button.component({
-          children: [badgeForId(adminGroup.id()), ' ', adminGroup.namePlural()],
+        Button.component(
+          {
             icon: !everyone && !members ? 'fas fa-check' : true,
             disabled: !everyone && !members,
             onclick: (e) => {
               if (e.shiftKey) e.stopPropagation();
               this.save([]);
             },
-        })
+          },
+          [badgeForId(adminGroup.id()), ' ', adminGroup.namePlural()]
+        )
       );
 
       [].push.apply(
-        this.props.children,
+        children,
         app.store
           .all('groups')
           .filter((group) => [Group.ADMINISTRATOR_ID, Group.GUEST_ID, Group.MEMBER_ID].indexOf(group.id()) === -1)
           .map((group) =>
-            Button.component({
-              children: [badgeForId(group.id()), ' ', group.namePlural()],
+            Button.component(
+              {
                 icon: groupIds.indexOf(group.id()) !== -1 ? 'fas fa-check' : true,
                 onclick: (e) => {
                   if (e.shiftKey) e.stopPropagation();
                   this.toggle(group.id());
                 },
                 disabled: this.isGroupDisabled(group.id()) && this.isGroupDisabled(Group.MEMBER_ID) && this.isGroupDisabled(Group.GUEST_ID),
-            })
+              },
+              [badgeForId(group.id()), ' ', group.namePlural()]
+            )
           )
       );
     }
 
-    return super.view();
+    return super.view({ ...vnode, children });
   }
 
   save(groupIds) {
-    const permission = this.props.permission;
+    const permission = this.attrs.permission;
 
     app.data.permissions[permission] = groupIds;
 
     app.request({
       method: 'POST',
       url: app.forum.attribute('apiUrl') + '/permission',
-      data: { permission, groupIds },
+      body: { permission, groupIds },
     });
   }
 
   toggle(groupId) {
-    const permission = this.props.permission;
+    const permission = this.attrs.permission;
 
     let groupIds = app.data.permissions[permission] || [];
 
@@ -143,6 +151,6 @@ export default class PermissionDropdown extends Dropdown {
   }
 
   isGroupDisabled(id) {
-    return filterByRequiredPermissions([id], this.props.permission).indexOf(id) === -1;
+    return filterByRequiredPermissions([id], this.attrs.permission).indexOf(id) === -1;
   }
 }

js/src/admin/components/PermissionGrid.js

@@ -6,7 +6,9 @@ import ItemList from '../../common/utils/ItemList';
 import icon from '../../common/helpers/icon';
 
 export default class PermissionGrid extends Component {
-  init() {
+  oninit(vnode) {
+    super.oninit(vnode);
+
     this.permissions = this.permissionItems().toArray();
   }
 

js/src/admin/components/SessionDropdown.js

@@ -9,18 +9,16 @@ import ItemList from '../../common/utils/ItemList';
  * avatar/name, with a dropdown of session controls.
  */
 export default class SessionDropdown extends Dropdown {
-  static initProps(props) {
-    super.initProps(props);
+  static initAttrs(attrs) {
+    super.initAttrs(attrs);
 
-    props.className = 'SessionDropdown';
-    props.buttonClassName = 'Button Button--user Button--flat';
-    props.menuClassName = 'Dropdown-menu--right';
+    attrs.className = 'SessionDropdown';
+    attrs.buttonClassName = 'Button Button--user Button--flat';
+    attrs.menuClassName = 'Dropdown-menu--right';
   }
 
-  view() {
-    this.props.children = this.items().toArray();
-
-    return super.view();
+  view(vnode) {
+    return super.view({ ...vnode, children: this.items().toArray() });
   }
 
   getButtonContent() {
@@ -39,11 +37,13 @@ export default class SessionDropdown extends Dropdown {
 
     items.add(
       'logOut',
-      Button.component({
+      Button.component(
+        {
           icon: 'fas fa-sign-out-alt',
-        children: app.translator.trans('core.admin.header.log_out_button'),
           onclick: app.session.logout.bind(app.session),
-      }),
+        },
+        app.translator.trans('core.admin.header.log_out_button')
+      ),
       -100
     );
 

js/src/admin/components/SettingDropdown.js

@@ -3,23 +3,30 @@ import Button from '../../common/components/Button';
 import saveSettings from '../utils/saveSettings';
 
 export default class SettingDropdown extends SelectDropdown {
-  static initProps(props) {
-    super.initProps(props);
+  static initAttrs(attrs) {
+    super.initAttrs(attrs);
 
-    props.className = 'SettingDropdown';
-    props.buttonClassName = 'Button Button--text';
-    props.caretIcon = 'fas fa-caret-down';
-    props.defaultLabel = 'Custom';
+    attrs.className = 'SettingDropdown';
+    attrs.buttonClassName = 'Button Button--text';
+    attrs.caretIcon = 'fas fa-caret-down';
+    attrs.defaultLabel = 'Custom';
+  }
 
-    props.children = props.options.map(({ value, label }) => {
-      const active = app.data.settings[props.key] === value;
+  view(vnode) {
+    return super.view({
+      ...vnode,
+      children: this.attrs.options.map(({ value, label }) => {
+        const active = app.data.settings[this.attrs.key] === value;
 
-      return Button.component({
-        children: label,
+        return Button.component(
+          {
             icon: active ? 'fas fa-check' : true,
-        onclick: saveSettings.bind(this, { [props.key]: value }),
+            onclick: saveSettings.bind(this, { [this.attrs.key]: value }),
             active,
-      });
+          },
+          label
+        );
+      }),
     });
   }
 }

js/src/admin/components/SettingsModal.js

@@ -3,7 +3,9 @@ import Button from '../../common/components/Button';
 import saveSettings from '../utils/saveSettings';
 
 export default class SettingsModal extends Modal {
-  init() {
+  oninit(vnode) {
+    super.oninit(vnode);
+
     this.settings = {};
     this.loading = false;
   }
@@ -33,7 +35,7 @@ export default class SettingsModal extends Modal {
   }
 
   setting(key, fallback = '') {
-    this.settings[key] = this.settings[key] || m.prop(app.data.settings[key] || fallback);
+    this.settings[key] = this.settings[key] || m.stream(app.data.settings[key] || fallback);
 
     return this.settings[key];
   }

js/src/admin/components/UploadImageButton.js

@@ -1,32 +1,28 @@
 import Button from '../../common/components/Button';
 
 export default class UploadImageButton extends Button {
-  init() {
-    this.loading = false;
-  }
+  loading = false;
 
-  view() {
-    this.props.loading = this.loading;
-    this.props.className = (this.props.className || '') + ' Button';
+  view(vnode) {
+    this.attrs.loading = this.loading;
+    this.attrs.className = (this.attrs.className || '') + ' Button';
 
-    if (app.data.settings[this.props.name + '_path']) {
-      this.props.onclick = this.remove.bind(this);
-      this.props.children = app.translator.trans('core.admin.upload_image.remove_button');
+    if (app.data.settings[this.attrs.name + '_path']) {
+      this.attrs.onclick = this.remove.bind(this);
 
       return (
         <div>
           <p>
-            <img src={app.forum.attribute(this.props.name + 'Url')} alt="" />
+            <img src={app.forum.attribute(this.attrs.name + 'Url')} alt="" />
           </p>
-          <p>{super.view()}</p>
+          <p>{super.view({ ...vnode, children: app.translator.trans('core.admin.upload_image.remove_button') })}</p>
         </div>
       );
     } else {
-      this.props.onclick = this.upload.bind(this);
-      this.props.children = app.translator.trans('core.admin.upload_image.upload_button');
+      this.attrs.onclick = this.upload.bind(this);
     }
 
-    return super.view();
+    return super.view({ ...vnode, children: app.translator.trans('core.admin.upload_image.upload_button') });
   }
 
   /**
@@ -42,8 +38,8 @@ export default class UploadImageButton extends Button {
       .hide()
       .click()
       .on('change', (e) => {
-        const data = new FormData();
-        data.append(this.props.name, $(e.target)[0].files[0]);
+        const body = new FormData();
+        body.append(this.attrs.name, $(e.target)[0].files[0]);
 
         this.loading = true;
         m.redraw();
@@ -53,7 +49,7 @@ export default class UploadImageButton extends Button {
             method: 'POST',
             url: this.resourceUrl(),
             serialize: (raw) => raw,
-            data,
+            body,
           })
           .then(this.success.bind(this), this.failure.bind(this));
       });
@@ -75,7 +71,7 @@ export default class UploadImageButton extends Button {
   }
 
   resourceUrl() {
-    return app.forum.attribute('apiUrl') + '/' + this.props.name;
+    return app.forum.attribute('apiUrl') + '/' + this.attrs.name;
   }
 
   /**

js/src/admin/routes.js

@@ -12,11 +12,11 @@ import MailPage from './components/MailPage';
  */
 export default function (app) {
   app.routes = {
-    dashboard: { path: '/', component: DashboardPage.component() },
-    basics: { path: '/basics', component: BasicsPage.component() },
-    permissions: { path: '/permissions', component: PermissionsPage.component() },
-    appearance: { path: '/appearance', component: AppearancePage.component() },
-    extensions: { path: '/extensions', component: ExtensionsPage.component() },
-    mail: { path: '/mail', component: MailPage.component() },
+    dashboard: { path: '/', component: DashboardPage },
+    basics: { path: '/basics', component: BasicsPage },
+    permissions: { path: '/permissions', component: PermissionsPage },
+    appearance: { path: '/appearance', component: AppearancePage },
+    extensions: { path: '/extensions', component: ExtensionsPage },
+    mail: { path: '/mail', component: MailPage },
   };
 }

js/src/admin/utils/saveSettings.js

@@ -7,7 +7,7 @@ export default function saveSettings(settings) {
     .request({
       method: 'POST',
       url: app.forum.attribute('apiUrl') + '/settings',
-      data: settings,
+      body: settings,
     })
     .catch((error) => {
       app.data.settings = oldSettings;

js/src/common/Application.js

@@ -189,8 +189,9 @@ export default class Application {
   }
 
   mount(basePath = '') {
-    m.mount(document.getElementById('modal'), <ModalManager state={this.modal} />);
-    m.mount(document.getElementById('alerts'), <AlertManager state={this.alerts} />);
+    // An object with a callable view property is used in order to pass arguments to the component; see https://mithril.js.org/mount.html
+    m.mount(document.getElementById('modal'), { view: () => ModalManager.component({ state: this.modal }) });
+    m.mount(document.getElementById('alerts'), { view: () => AlertManager.component({ state: this.alerts }) });
 
     this.drawer = new Drawer();
 
@@ -263,7 +264,7 @@ export default class Application {
 
   updateTitle() {
     const count = this.titleCount ? `(${this.titleCount}) ` : '';
-    const pageTitleWithSeparator = this.title && m.route() !== '/' ? this.title + ' - ' : '';
+    const pageTitleWithSeparator = this.title && m.route.get() !== '/' ? this.title + ' - ' : '';
     const title = this.forum.attribute('title');
     document.title = count + pageTitleWithSeparator + title;
   }
@@ -342,16 +343,14 @@ export default class Application {
 
     // Now make the request. If it's a failure, inspect the error that was
     // returned and show an alert containing its contents.
-    const deferred = m.deferred();
-
-    m.request(options).then(
-      (response) => deferred.resolve(response),
+    return m.request(options).then(
+      (response) => response,
       (error) => {
-        let children;
+        let content;
 
         switch (error.status) {
           case 422:
-            children = error.response.errors
+            content = error.response.errors
               .map((error) => [error.detail, <br />])
               .reduce((a, b) => a.concat(b), [])
               .slice(0, -1);
@@ -359,30 +358,31 @@ export default class Application {
 
           case 401:
           case 403:
-            children = app.translator.trans('core.lib.error.permission_denied_message');
+            content = app.translator.trans('core.lib.error.permission_denied_message');
             break;
 
           case 404:
           case 410:
-            children = app.translator.trans('core.lib.error.not_found_message');
+            content = app.translator.trans('core.lib.error.not_found_message');
             break;
 
           case 429:
-            children = app.translator.trans('core.lib.error.rate_limit_exceeded_message');
+            content = app.translator.trans('core.lib.error.rate_limit_exceeded_message');
             break;
 
           default:
-            children = app.translator.trans('core.lib.error.generic_message');
+            content = app.translator.trans('core.lib.error.generic_message');
         }
 
         const isDebug = app.forum.attribute('debug');
         // contains a formatted errors if possible, response must be an JSON API array of errors
         // the details property is decoded to transform escaped characters such as '\n'
-        const formattedError = error.response && Array.isArray(error.response.errors) && error.response.errors.map((e) => decodeURI(e.detail));
+        const errors = error.response && error.response.errors;
+        const formattedError = Array.isArray(errors) && errors[0] && errors[0].detail && errors.map((e) => decodeURI(e.detail));
 
         error.alert = {
           type: 'error',
-          children,
+          content,
           controls: isDebug && [
             <Button className="Button Button--link" onclick={this.showDebug.bind(this, error, formattedError)}>
               Debug
@@ -404,14 +404,12 @@ export default class Application {
             console.groupEnd();
           }
 
-          this.requestErrorAlert = this.alerts.show(error.alert);
+          this.requestErrorAlert = this.alerts.show(error.alert, error.alert.content);
         }
 
-        deferred.reject(error);
+        return Promise.reject(error);
       }
     );
-
-    return deferred.promise;
   }
 
   /**
@@ -434,9 +432,19 @@ export default class Application {
    * @public
    */
   route(name, params = {}) {
-    const url = this.routes[name].path.replace(/:([^\/]+)/g, (m, key) => extract(params, key));
-    const queryString = m.route.buildQueryString(params);
-    const prefix = m.route.mode === 'pathname' ? app.forum.attribute('basePath') : '';
+    const route = this.routes[name];
+
+    if (!route) throw new Error(`Route '${name}' does not exist`);
+
+    const url = route.path.replace(/:([^\/]+)/g, (m, key) => extract(params, key));
+
+    // Remove falsy values in params to avoid having urls like '/?sort&q'
+    for (const key in params) {
+      if (params.hasOwnProperty(key) && !params[key]) delete params[key];
+    }
+
+    const queryString = m.buildQueryString(params);
+    const prefix = m.route.prefix === '' ? this.forum.attribute('basePath') : '';
 
     return prefix + url + (queryString ? '?' + queryString : '');
   }

js/src/common/Component.js

@@ -1,221 +0,0 @@
-/*
- * This file is part of Flarum.
- *
- * (c) Toby Zerner <toby.zerner@gmail.com>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-/**
- * The `Component` class defines a user interface 'building block'. A component
- * can generate a virtual DOM to be rendered on each redraw.
- *
- * An instance's virtual DOM can be retrieved directly using the {@link
- * Component#render} method.
- *
- * @example
- * this.myComponentInstance = new MyComponent({foo: 'bar'});
- * return m('div', this.myComponentInstance.render());
- *
- * Alternatively, components can be nested, letting Mithril take care of
- * instance persistence. For this, the static {@link Component.component} method
- * can be used.
- *
- * @example
- * return m('div', MyComponent.component({foo: 'bar'));
- *
- * @see https://lhorie.github.io/mithril/mithril.component.html
- * @abstract
- */
-export default class Component {
-  /**
-   * @param {Object} props
-   * @param {Array|Object} children
-   * @public
-   */
-  constructor(props = {}, children = null) {
-    if (children) props.children = children;
-
-    this.constructor.initProps(props);
-
-    /**
-     * The properties passed into the component.
-     *
-     * @type {Object}
-     */
-    this.props = props;
-
-    /**
-     * The root DOM element for the component.
-     *
-     * @type DOMElement
-     * @public
-     */
-    this.element = null;
-
-    /**
-     * Whether or not to retain the component's subtree on redraw.
-     *
-     * @type {boolean}
-     * @public
-     */
-    this.retain = false;
-
-    this.init();
-  }
-
-  /**
-   * Called when the component is constructed.
-   *
-   * @protected
-   */
-  init() {}
-
-  /**
-   * Called when the component is destroyed, i.e. after a redraw where it is no
-   * longer a part of the view.
-   *
-   * @see https://lhorie.github.io/mithril/mithril.component.html#unloading-components
-   * @param {Object} e
-   * @public
-   */
-  onunload() {}
-
-  /**
-   * Get the renderable virtual DOM that represents the component's view.
-   *
-   * This should NOT be overridden by subclasses. Subclasses wishing to define
-   * their virtual DOM should override Component#view instead.
-   *
-   * @example
-   * this.myComponentInstance = new MyComponent({foo: 'bar'});
-   * return m('div', this.myComponentInstance.render());
-   *
-   * @returns {Object}
-   * @final
-   * @public
-   */
-  render() {
-    const vdom = this.retain ? { subtree: 'retain' } : this.view();
-
-    // Override the root element's config attribute with our own function, which
-    // will set the component instance's element property to the root DOM
-    // element, and then run the component class' config method.
-    vdom.attrs = vdom.attrs || {};
-
-    const originalConfig = vdom.attrs.config;
-
-    vdom.attrs.config = (...args) => {
-      this.element = args[0];
-      this.config.apply(this, args.slice(1));
-      if (originalConfig) originalConfig.apply(this, args);
-    };
-
-    return vdom;
-  }
-
-  /**
-   * Returns a jQuery object for this component's element. If you pass in a
-   * selector string, this method will return a jQuery object, using the current
-   * element as its buffer.
-   *
-   * For example, calling `component.$('li')` will return a jQuery object
-   * containing all of the `li` elements inside the DOM element of this
-   * component.
-   *
-   * @param {String} [selector] a jQuery-compatible selector string
-   * @returns {jQuery} the jQuery object for the DOM node
-   * @final
-   * @public
-   */
-  $(selector) {
-    const $element = $(this.element);
-
-    return selector ? $element.find(selector) : $element;
-  }
-
-  /**
-   * Called after the component's root element is redrawn. This hook can be used
-   * to perform any actions on the DOM, both on the initial draw and any
-   * subsequent redraws. See Mithril's documentation for more information.
-   *
-   * @see https://lhorie.github.io/mithril/mithril.html#the-config-attribute
-   * @param {Boolean} isInitialized
-   * @param {Object} context
-   * @param {Object} vdom
-   * @public
-   */
-  config() {}
-
-  /**
-   * Get the virtual DOM that represents the component's view.
-   *
-   * @return {Object} The virtual DOM
-   * @protected
-   */
-  view() {
-    throw new Error('Component#view must be implemented by subclass');
-  }
-
-  /**
-   * Get a Mithril component object for this component, preloaded with props.
-   *
-   * @see https://lhorie.github.io/mithril/mithril.component.html
-   * @param {Object} [props] Properties to set on the component
-   * @param children
-   * @return {Object} The Mithril component object
-   * @property {function} controller
-   * @property {function} view
-   * @property {Object} component The class of this component
-   * @property {Object} props The props that were passed to the component
-   * @public
-   */
-  static component(props = {}, children = null) {
-    const componentProps = Object.assign({}, props);
-
-    if (children) componentProps.children = children;
-
-    this.initProps(componentProps);
-
-    // Set up a function for Mithril to get the component's view. It will accept
-    // the component's controller (which happens to be the component itself, in
-    // our case), update its props with the ones supplied, and then render the view.
-    const view = (component) => {
-      component.props = componentProps;
-      return component.render();
-    };
-
-    // Mithril uses this property on the view function to cache component
-    // controllers between redraws, thus persisting component state.
-    view.$original = this.prototype.view;
-
-    // Our output object consists of a controller constructor + a view function
-    // which Mithril will use to instantiate and render the component. We also
-    // attach a reference to the props that were passed through and the
-    // component's class for reference.
-    const output = {
-      controller: this.bind(undefined, componentProps),
-      view: view,
-      props: componentProps,
-      component: this,
-    };
-
-    // If a `key` prop was set, then we'll assume that we want that to actually
-    // show up as an attribute on the component object so that Mithril's key
-    // algorithm can be applied.
-    if (componentProps.key) {
-      output.attrs = { key: componentProps.key };
-    }
-
-    return output;
-  }
-
-  /**
-   * Initialize the component's props.
-   *
-   * @param {Object} props
-   * @public
-   */
-  static initProps(props) {}
-}

js/src/common/Component.ts

@@ -0,0 +1,136 @@
+import * as Mithril from 'mithril';
+
+export type ComponentAttrs = {
+  className?: string;
+
+  [key: string]: any;
+};
+
+/**
+ * The `Component` class defines a user interface 'building block'. A component
+ * generates a virtual DOM to be rendered on each redraw.
+ *
+ * Essentially, this is a wrapper for Mithril's components that adds several useful features:
+ *
+ *  - In the `oninit` and `onbeforeupdate` lifecycle hooks, we store vnode attrs in `this.attrs.
+ *    This allows us to use attrs across components without having to pass the vnode to every single
+ *    method.
+ *  - The static `initAttrs` method allows a convenient way to provide defaults (or to otherwise modify)
+ *    the attrs that have been passed into a component.
+ *  - When the component is created in the DOM, we store its DOM element under `this.element`; this lets
+ *    us use jQuery to modify child DOM state from internal methods via the `this.$()` method.
+ *  - A convenience `component` method, which serves as an alternative to hyperscript and JSX.
+ *
+ * As with other Mithril components, components extending Component can be initialized
+ * and nested using JSX, hyperscript, or a combination of both. The `component` method can also
+ * be used.
+ *
+ * @example
+ * return m('div', <MyComponent foo="bar"><p>Hello World</p></MyComponent>);
+ *
+ * @example
+ * return m('div', MyComponent.component({foo: 'bar'), m('p', 'Hello World!'));
+ *
+ * @see https://mithril.js.org/components.html
+ */
+export default abstract class Component<T extends ComponentAttrs = any> implements Mithril.ClassComponent<T> {
+  /**
+   * The root DOM element for the component.
+   */
+  protected element!: Element;
+
+  /**
+   * The attributes passed into the component.
+   *
+   * @see https://mithril.js.org/components.html#passing-data-to-components
+   */
+  protected attrs!: T;
+
+  /**
+   * @inheritdoc
+   */
+  abstract view(vnode: Mithril.Vnode<T, this>): Mithril.Children;
+
+  /**
+   * @inheritdoc
+   */
+  oninit(vnode: Mithril.Vnode<T, this>) {
+    this.setAttrs(vnode.attrs);
+  }
+
+  /**
+   * @inheritdoc
+   */
+  oncreate(vnode: Mithril.VnodeDOM<T, this>) {
+    this.element = vnode.dom;
+  }
+
+  /**
+   * @inheritdoc
+   */
+  onbeforeupdate(vnode: Mithril.VnodeDOM<T, this>) {
+    this.setAttrs(vnode.attrs);
+  }
+
+  /**
+   * Returns a jQuery object for this component's element. If you pass in a
+   * selector string, this method will return a jQuery object, using the current
+   * element as its buffer.
+   *
+   * For example, calling `component.$('li')` will return a jQuery object
+   * containing all of the `li` elements inside the DOM element of this
+   * component.
+   *
+   * @param {String} [selector] a jQuery-compatible selector string
+   * @returns {jQuery} the jQuery object for the DOM node
+   * @final
+   */
+  protected $(selector) {
+    const $element = $(this.element);
+
+    return selector ? $element.find(selector) : $element;
+  }
+
+  /**
+   * Convenience method to attach a component without JSX.
+   * Has the same effect as calling `m(THIS_CLASS, attrs, children)`.
+   *
+   * @see https://mithril.js.org/hyperscript.html#mselector,-attributes,-children
+   */
+  static component(attrs = {}, children = null): Mithril.Vnode {
+    const componentAttrs = Object.assign({}, attrs);
+
+    return m(this as any, componentAttrs, children);
+  }
+
+  /**
+   * Saves a reference to the vnode attrs after running them through initAttrs,
+   * and checking for common issues.
+   */
+  private setAttrs(attrs: T = {} as T): void {
+    (this.constructor as typeof Component).initAttrs(attrs);
+
+    if (attrs) {
+      if ('children' in attrs) {
+        throw new Error(
+          `[${
+            (this.constructor as any).name
+          }] The "children" attribute of attrs should never be used. Either pass children in as the vnode children or rename the attribute`
+        );
+      }
+
+      if ('tag' in attrs) {
+        throw new Error(`[${(this.constructor as any).name}] You cannot use the "tag" attribute name with Mithril 2.`);
+      }
+    }
+
+    this.attrs = attrs;
+  }
+
+  /**
+   * Initialize the component's attrs.
+   *
+   * This can be used to assign default values for missing, optional attrs.
+   */
+  protected static initAttrs<T>(attrs: T): void {}
+}

js/src/common/Fragment.ts

@@ -0,0 +1,74 @@
+import * as Mithril from 'mithril';
+
+/**
+ * The `Fragment` class represents a chunk of DOM that is rendered once with Mithril and then takes
+ * over control of its own DOM and lifecycle.
+ *
+ * This is very similar to the `Component` wrapper class, but is used for more fine-grained control over
+ * the rendering and display of some significant chunks of the DOM. In contrast to components, fragments
+ * do not offer Mithril's lifecycle hooks.
+ *
+ * Use this when you want to enjoy the benefits of JSX / VDOM for initial rendering, combined with
+ * small helper methods that then make updates to that DOM directly, instead of fully redrawing
+ * everything through Mithril.
+ *
+ * This should only be used when necessary, and only with `m.render`. If you are unsure whether you need
+ * this or `Component, you probably need `Component`.
+ */
+export default abstract class Fragment {
+  /**
+   * The root DOM element for the fragment.
+   */
+  protected element!: Element;
+
+  /**
+   * Returns a jQuery object for this fragment's element. If you pass in a
+   * selector string, this method will return a jQuery object, using the current
+   * element as its buffer.
+   *
+   * For example, calling `fragment.$('li')` will return a jQuery object
+   * containing all of the `li` elements inside the DOM element of this
+   * fragment.
+   *
+   * @param {String} [selector] a jQuery-compatible selector string
+   * @returns {jQuery} the jQuery object for the DOM node
+   * @final
+   */
+  public $(selector) {
+    const $element = $(this.element);
+
+    return selector ? $element.find(selector) : $element;
+  }
+
+  /**
+   * Get the renderable virtual DOM that represents the fragment's view.
+   *
+   * This should NOT be overridden by subclasses. Subclasses wishing to define
+   * their virtual DOM should override Fragment#view instead.
+   *
+   * @example
+   * const fragment = new MyFragment();
+   * m.render(document.body, fragment.render());
+   *
+   * @final
+   */
+  public render(): Mithril.Vnode<Mithril.Attributes, this> {
+    const vdom = this.view();
+
+    vdom.attrs = vdom.attrs || {};
+
+    const originalOnCreate = vdom.attrs.oncreate;
+
+    vdom.attrs.oncreate = (vnode) => {
+      this.element = vnode.dom;
+      if (originalOnCreate) originalOnCreate.apply(this, [vnode]);
+    };
+
+    return vdom;
+  }
+
+  /**
+   * Creates a view out of virtual elements.
+   */
+  abstract view(): Mithril.Vnode<Mithril.Attributes, this>;
+}

js/src/common/Model.js

@@ -161,7 +161,7 @@ export default class Model {
           {
             method: this.exists ? 'PATCH' : 'POST',
             url: app.forum.attribute('apiUrl') + this.apiEndpoint(),
-            data: request,
+            body: request,
           },
           options
         )
@@ -180,7 +180,7 @@ export default class Model {
         // old data! We'll revert to that and let others handle the error.
         (response) => {
           this.pushData(oldData);
-          m.lazyRedraw();
+          m.redraw();
           throw response;
         }
       );
@@ -189,13 +189,13 @@ export default class Model {
   /**
    * Send a request to delete the resource.
    *
-   * @param {Object} data Data to send along with the DELETE request.
+   * @param {Object} body Data to send along with the DELETE request.
    * @param {Object} [options]
    * @return {Promise}
    * @public
    */
-  delete(data, options = {}) {
-    if (!this.exists) return m.deferred().resolve().promise;
+  delete(body, options = {}) {
+    if (!this.exists) return Promise.resolve();
 
     return app
       .request(
@@ -203,7 +203,7 @@ export default class Model {
           {
             method: 'DELETE',
             url: app.forum.attribute('apiUrl') + this.apiEndpoint(),
-            data,
+            body,
           },
           options
         )

js/src/common/Session.js

@@ -30,13 +30,13 @@ export default class Session {
    * @return {Promise}
    * @public
    */
-  login(data, options = {}) {
+  login(body, options = {}) {
     return app.request(
       Object.assign(
         {
           method: 'POST',
-          url: app.forum.attribute('baseUrl') + '/login',
-          data,
+          url: `${app.forum.attribute('baseUrl')}/login`,
+          body,
         },
         options
       )
@@ -49,6 +49,6 @@ export default class Session {
    * @public
    */
   logout() {
-    window.location = app.forum.attribute('baseUrl') + '/logout?token=' + this.csrfToken;
+    window.location = `${app.forum.attribute('baseUrl')}/logout?token=${this.csrfToken}`;
   }
 }

js/src/common/Store.js

@@ -82,13 +82,13 @@ export default class Store {
    * @public
    */
   find(type, id, query = {}, options = {}) {
-    let data = query;
+    let params = query;
     let url = app.forum.attribute('apiUrl') + '/' + type;
 
     if (id instanceof Array) {
       url += '?filter[id]=' + id.join(',');
     } else if (typeof id === 'object') {
-      data = id;
+      params = id;
     } else if (id) {
       url += '/' + id;
     }
@@ -99,7 +99,7 @@ export default class Store {
           {
             method: 'GET',
             url,
-            data,
+            params,
           },
           options
         )

js/src/common/Translator.js

@@ -1,4 +1,3 @@
-import User from './models/User';
 import username from './helpers/username';
 import extract from './utils/extract';
 
@@ -71,18 +70,34 @@ export default class Translator {
       const match = part.match(new RegExp('{([a-z0-9_]+)}|<(/?)([a-z0-9_]+)>', 'i'));
 
       if (match) {
+        // Either an opening or closing tag.
         if (match[1]) {
           open[0].push(input[match[1]]);
         } else if (match[3]) {
           if (match[2]) {
+            // Closing tag. We start by removing all raw children (generally in the form of strings) from the temporary
+            // holding array, then run them through m.fragment to convert them to vnodes. Usually this will just give us a
+            // text vnode, but using m.fragment as opposed to an explicit conversion should be more flexible. This is necessary because
+            // otherwise, our generated vnode will have raw strings as its children, and mithril expects vnodes.
+            // Finally, we add the now-processed vnodes back onto the holding array (which is the same object in memory as the
+            // children array of the vnode we are currently processing), and remove the reference to the holding array so that
+            // further text will be added to the full set of returned elements.
+            const rawChildren = open[0].splice(0, open[0].length);
+            open[0].push(...m.fragment(rawChildren).children);
             open.shift();
           } else {
+            // If a vnode with a matching tag was provided in the translator input, we use that. Otherwise, we create a new vnode
+            // with this tag, and an empty children array (since we're expecting to insert children, as that's the point of having this in translator)
             let tag = input[match[3]] || { tag: match[3], children: [] };
             open[0].push(tag);
+            // Insert the tag's children array as the first element of open, so that text in between the opening
+            // and closing tags will be added to the tag's children, not to the full set of returned elements.
             open.unshift(tag.children || tag);
           }
         }
       } else {
+        // Not an html tag, we add it to open[0], which is either the full set of returned elements (vnodes and text),
+        // or if an html tag is currently being processed, the children attribute of that html tag's vnode.
         open[0].push(part);
       }
     });

js/src/common/compat.js

@@ -13,6 +13,7 @@ import RequestError from './utils/RequestError';
 import abbreviateNumber from './utils/abbreviateNumber';
 import * as string from './utils/string';
 import SubtreeRetainer from './utils/SubtreeRetainer';
+import setRouteWithForcedRefresh from './utils/setRouteWithForcedRefresh';
 import extract from './utils/extract';
 import ScrollListener from './utils/ScrollListener';
 import stringToColor from './utils/stringToColor';
@@ -22,6 +23,7 @@ import classList from './utils/classList';
 import extractText from './utils/extractText';
 import formatNumber from './utils/formatNumber';
 import mapRoutes from './utils/mapRoutes';
+import withAttr from './utils/withAttr';
 import Notification from './models/Notification';
 import User from './models/User';
 import Post from './models/Post';
@@ -62,6 +64,7 @@ import highlight from './helpers/highlight';
 import username from './helpers/username';
 import userOnline from './helpers/userOnline';
 import listItems from './helpers/listItems';
+import Fragment from './Fragment';
 
 export default {
   extend: extend,
@@ -83,11 +86,13 @@ export default {
   'utils/ScrollListener': ScrollListener,
   'utils/stringToColor': stringToColor,
   'utils/subclassOf': subclassOf,
+  'utils/setRouteWithForcedRefresh': setRouteWithForcedRefresh,
   'utils/patchMithril': patchMithril,
   'utils/classList': classList,
   'utils/extractText': extractText,
   'utils/formatNumber': formatNumber,
   'utils/mapRoutes': mapRoutes,
+  'utils/withAttr': withAttr,
   'models/Notification': Notification,
   'models/User': User,
   'models/Post': Post,
@@ -95,6 +100,7 @@ export default {
   'models/Group': Group,
   'models/Forum': Forum,
   Component: Component,
+  Fragment: Fragment,
   Translator: Translator,
   'components/AlertManager': AlertManager,
   'components/Page': Page,

js/src/common/components/Alert.js

@@ -7,7 +7,7 @@ import extract from '../utils/extract';
  * The `Alert` component represents an alert box, which contains a message,
  * some controls, and may be dismissible.
  *
- * The alert may have the following special props:
+ * ### Attrs
  *
  * - `type` The type of alert this is. Will be used to give the alert a class
  *   name of `Alert--{type}`.
@@ -15,16 +15,16 @@ import extract from '../utils/extract';
  * - `dismissible` Whether or not the alert can be dismissed.
  * - `ondismiss` A callback to run when the alert is dismissed.
  *
- * All other props will be assigned as attributes on the alert element.
+ * All other attrs will be assigned as attributes on the DOM element.
  */
 export default class Alert extends Component {
-  view() {
-    const attrs = Object.assign({}, this.props);
+  view(vnode) {
+    const attrs = Object.assign({}, this.attrs);
 
     const type = extract(attrs, 'type');
     attrs.className = 'Alert Alert--' + type + ' ' + (attrs.className || '');
 
-    const children = extract(attrs, 'children');
+    const content = extract(attrs, 'content') || vnode.children;
     const controls = extract(attrs, 'controls') || [];
 
     // If the alert is meant to be dismissible (which is the case by default),
@@ -40,7 +40,7 @@ export default class Alert extends Component {
 
     return (
       <div {...attrs}>
-        <span className="Alert-body">{children}</span>
+        <span className="Alert-body">{content}</span>
         <ul className="Alert-controls">{listItems(controls.concat(dismissControl))}</ul>
       </div>
     );

js/src/common/components/AlertManager.js

@@ -6,8 +6,10 @@ import Alert from './Alert';
  * be shown and dismissed.
  */
 export default class AlertManager extends Component {
-  init() {
-    this.state = this.props.state;
+  oninit(vnode) {
+    super.oninit(vnode);
+
+    this.state = this.attrs.state;
   }
 
   view() {
@@ -15,17 +17,12 @@ export default class AlertManager extends Component {
       <div className="AlertManager">
         {Object.entries(this.state.getActiveAlerts()).map(([key, alert]) => (
           <div className="AlertManager-alert">
-            {(alert.componentClass || Alert).component({ ...alert.attrs, ondismiss: this.state.dismiss.bind(this.state, key) })}
+            <alert.componentClass {...alert.attrs} ondismiss={this.state.dismiss.bind(this.state, key)}>
+              {alert.children}
+            </alert.componentClass>
           </div>
         ))}
       </div>
     );
   }
-
-  config(isInitialized, context) {
-    // Since this component is 'above' the content of the page (that is, it is a
-    // part of the global UI that persists between routes), we will flag the DOM
-    // to be retained across route changes.
-    context.retain = true;
-  }
 }

js/src/common/components/Badge.js

@@ -6,18 +6,18 @@ import extract from '../utils/extract';
  * The `Badge` component represents a user/discussion badge, indicating some
  * status (e.g. a discussion is stickied, a user is an admin).
  *
- * A badge may have the following special props:
+ * A badge may have the following special attrs:
  *
  * - `type` The type of badge this is. This will be used to give the badge a
  *   class name of `Badge--{type}`.
  * - `icon` The name of an icon to show inside the badge.
  * - `label`
  *
- * All other props will be assigned as attributes on the badge element.
+ * All other attrs will be assigned as attributes on the badge element.
  */
 export default class Badge extends Component {
   view() {
-    const attrs = Object.assign({}, this.props);
+    const attrs = Object.assign({}, this.attrs);
     const type = extract(attrs, 'type');
     const iconName = extract(attrs, 'icon');
 
@@ -27,9 +27,9 @@ export default class Badge extends Component {
     return <span {...attrs}>{iconName ? icon(iconName, { className: 'Badge-icon' }) : m.trust('&nbsp;')}</span>;
   }
 
-  config(isInitialized) {
-    if (isInitialized) return;
+  oncreate(vnode) {
+    super.oncreate(vnode);
 
-    if (this.props.label) this.$().tooltip();
+    if (this.attrs.label) this.$().tooltip();
   }
 }

js/src/common/components/Button.js

@@ -1,12 +1,15 @@
 import Component from '../Component';
 import icon from '../helpers/icon';
+import classList from '../utils/classList';
 import extract from '../utils/extract';
 import extractText from '../utils/extractText';
 import LoadingIndicator from './LoadingIndicator';
 
 /**
  * The `Button` component defines an element which, when clicked, performs an
- * action. The button may have the following special props:
+ * action.
+ *
+ * ### Attrs
  *
  * - `icon` The name of the icon class. If specified, the button will be given a
  *   'has-icon' class name.
@@ -15,41 +18,38 @@ import LoadingIndicator from './LoadingIndicator';
  *   removed.
  * - `loading` Whether or not the button should be in a disabled loading state.
  *
- * All other props will be assigned as attributes on the button element.
+ * All other attrs will be assigned as attributes on the button element.
  *
  * Note that a Button has no default class names. This is because a Button can
  * be used to represent any generic clickable control, like a menu item.
  */
 export default class Button extends Component {
-  view() {
-    const attrs = Object.assign({}, this.props);
+  view(vnode) {
+    const attrs = Object.assign({}, this.attrs);
 
-    delete attrs.children;
-
-    attrs.className = attrs.className || '';
     attrs.type = attrs.type || 'button';
 
     // If a tooltip was provided for buttons without additional content, we also
     // use this tooltip as text for screen readers
-    if (attrs.title && !this.props.children) {
+    if (attrs.title && !vnode.children) {
       attrs['aria-label'] = attrs.title;
     }
 
     // If nothing else is provided, we use the textual button content as tooltip
-    if (!attrs.title && this.props.children) {
-      attrs.title = extractText(this.props.children);
+    if (!attrs.title && vnode.children) {
+      attrs.title = extractText(vnode.children);
     }
 
     const iconName = extract(attrs, 'icon');
-    if (iconName) attrs.className += ' hasIcon';
 
     const loading = extract(attrs, 'loading');
     if (attrs.disabled || loading) {
-      attrs.className += ' disabled' + (loading ? ' loading' : '');
       delete attrs.onclick;
     }
 
-    return <button {...attrs}>{this.getButtonContent()}</button>;
+    attrs.className = classList([attrs.className, iconName && 'hasIcon', (attrs.disabled || loading) && 'disabled', loading && 'loading']);
+
+    return <button {...attrs}>{this.getButtonContent(vnode.children)}</button>;
   }
 
   /**
@@ -58,13 +58,13 @@ export default class Button extends Component {
    * @return {*}
    * @protected
    */
-  getButtonContent() {
-    const iconName = this.props.icon;
+  getButtonContent(children) {
+    const iconName = this.attrs.icon;
 
     return [
       iconName && iconName !== true ? icon(iconName, { className: 'Button-icon' }) : '',
-      this.props.children ? <span className="Button-label">{this.props.children}</span> : '',
-      this.props.loading ? LoadingIndicator.component({ size: 'tiny', className: 'LoadingIndicator--inline' }) : '',
+      children ? <span className="Button-label">{children}</span> : '',
+      this.attrs.loading ? <LoadingIndicator size="tiny" className="LoadingIndicator--inline" /> : '',
     ];
   }
 }

js/src/common/components/Checkbox.js

@@ -1,11 +1,13 @@
 import Component from '../Component';
 import LoadingIndicator from './LoadingIndicator';
 import icon from '../helpers/icon';
+import classList from '../utils/classList';
+import withAttr from '../utils/withAttr';
 
 /**
  * The `Checkbox` component defines a checkbox input.
  *
- * ### Props
+ * ### Attrs
  *
  * - `state` Whether or not the checkbox is checked.
  * - `className` The class name for the root element.
@@ -15,19 +17,24 @@ import icon from '../helpers/icon';
  * - `children` A text label to display next to the checkbox.
  */
 export default class Checkbox extends Component {
-  view() {
+  view(vnode) {
     // Sometimes, false is stored in the DB as '0'. This is a temporary
     // conversion layer until a more robust settings encoding is introduced
-    if (this.props.state === '0') this.props.state = false;
-    let className = 'Checkbox ' + (this.props.state ? 'on' : 'off') + ' ' + (this.props.className || '');
-    if (this.props.loading) className += ' loading';
-    if (this.props.disabled) className += ' disabled';
+    if (this.attrs.state === '0') this.attrs.state = false;
+
+    const className = classList([
+      'Checkbox',
+      this.attrs.state ? 'on' : 'off',
+      this.attrs.className,
+      this.attrs.loading && 'loading',
+      this.attrs.disabled && 'disabled',
+    ]);
 
     return (
       <label className={className}>
-        <input type="checkbox" checked={this.props.state} disabled={this.props.disabled} onchange={m.withAttr('checked', this.onchange.bind(this))} />
+        <input type="checkbox" checked={this.attrs.state} disabled={this.attrs.disabled} onchange={withAttr('checked', this.onchange.bind(this))} />
         <div className="Checkbox-display">{this.getDisplay()}</div>
-        {this.props.children}
+        {vnode.children}
       </label>
     );
   }
@@ -39,7 +46,7 @@ export default class Checkbox extends Component {
    * @protected
    */
   getDisplay() {
-    return this.props.loading ? LoadingIndicator.component({ size: 'tiny' }) : icon(this.props.state ? 'fas fa-check' : 'fas fa-times');
+    return this.attrs.loading ? <LoadingIndicator size="tiny" /> : icon(this.attrs.state ? 'fas fa-check' : 'fas fa-times');
   }
 
   /**
@@ -49,6 +56,6 @@ export default class Checkbox extends Component {
    * @protected
    */
   onchange(checked) {
-    if (this.props.onchange) this.props.onchange(checked, this);
+    if (this.attrs.onchange) this.attrs.onchange(checked, this);
   }
 }

js/src/common/components/ConfirmDocumentUnload.js

@@ -5,7 +5,7 @@ import Component from '../Component';
  * event handler that prevents closing the browser window/tab based on the
  * return value of a given callback prop.
  *
- * ### Props
+ * ### Attrs
  *
  * - `when` - a callback returning true when the browser should prompt for
  *            confirmation before closing the window/tab
@@ -17,21 +17,24 @@ import Component from '../Component';
  *
  */
 export default class ConfirmDocumentUnload extends Component {
-  config(isInitialized, context) {
-    if (isInitialized) return;
-
-    const handler = () => this.props.when() || undefined;
-
-    $(window).on('beforeunload', handler);
-
-    context.onunload = () => {
-      $(window).off('beforeunload', handler);
-    };
+  handler() {
+    return this.attrs.when() || undefined;
   }
 
-  view() {
+  oncreate(vnode) {
+    super.oncreate(vnode);
+
+    this.boundHandler = this.handler.bind(this);
+    $(window).on('beforeunload', this.boundHandler);
+  }
+
+  onremove() {
+    $(window).off('beforeunload', this.boundHandler);
+  }
+
+  view(vnode) {
     // To avoid having to render another wrapping <div> here, we assume that
     // this component is only wrapped around a single element / component.
-    return this.props.children[0];
+    return vnode.children[0];
   }
 }

js/src/common/components/Dropdown.js

@@ -6,7 +6,7 @@ import listItems from '../helpers/listItems';
  * The `Dropdown` component displays a button which, when clicked, shows a
  * dropdown menu beneath it.
  *
- * ### Props
+ * ### Attrs
  *
  * - `buttonClassName` A class name to apply to the dropdown toggle button.
  * - `menuClassName` A class name to apply to the dropdown menu.
@@ -19,33 +19,33 @@ import listItems from '../helpers/listItems';
  * The children will be displayed as a list inside of the dropdown menu.
  */
 export default class Dropdown extends Component {
-  static initProps(props) {
-    super.initProps(props);
-
-    props.className = props.className || '';
-    props.buttonClassName = props.buttonClassName || '';
-    props.menuClassName = props.menuClassName || '';
-    props.label = props.label || '';
-    props.caretIcon = typeof props.caretIcon !== 'undefined' ? props.caretIcon : 'fas fa-caret-down';
+  static initAttrs(attrs) {
+    attrs.className = attrs.className || '';
+    attrs.buttonClassName = attrs.buttonClassName || '';
+    attrs.menuClassName = attrs.menuClassName || '';
+    attrs.label = attrs.label || '';
+    attrs.caretIcon = typeof attrs.caretIcon !== 'undefined' ? attrs.caretIcon : 'fas fa-caret-down';
   }
 
-  init() {
+  oninit(vnode) {
+    super.oninit(vnode);
+
     this.showing = false;
   }
 
-  view() {
-    const items = this.props.children ? listItems(this.props.children) : [];
+  view(vnode) {
+    const items = vnode.children ? listItems(vnode.children) : [];
 
     return (
-      <div className={'ButtonGroup Dropdown dropdown ' + this.props.className + ' itemCount' + items.length + (this.showing ? ' open' : '')}>
-        {this.getButton()}
+      <div className={'ButtonGroup Dropdown dropdown ' + this.attrs.className + ' itemCount' + items.length + (this.showing ? ' open' : '')}>
+        {this.getButton(vnode.children)}
         {this.getMenu(items)}
       </div>
     );
   }
 
-  config(isInitialized) {
-    if (isInitialized) return;
+  oncreate(vnode) {
+    super.oncreate(vnode);
 
     // When opening the dropdown menu, work out if the menu goes beyond the
     // bottom of the viewport. If it does, we will apply class to make it show
@@ -53,8 +53,8 @@ export default class Dropdown extends Component {
     this.$().on('shown.bs.dropdown', () => {
       this.showing = true;
 
-      if (this.props.onshow) {
-        this.props.onshow();
+      if (this.attrs.onshow) {
+        this.attrs.onshow();
       }
 
       m.redraw();
@@ -76,8 +76,8 @@ export default class Dropdown extends Component {
     this.$().on('hidden.bs.dropdown', () => {
       this.showing = false;
 
-      if (this.props.onhide) {
-        this.props.onhide();
+      if (this.attrs.onhide) {
+        this.attrs.onhide();
       }
 
       m.redraw();
@@ -90,10 +90,10 @@ export default class Dropdown extends Component {
    * @return {*}
    * @protected
    */
-  getButton() {
+  getButton(children) {
     return (
-      <button className={'Dropdown-toggle ' + this.props.buttonClassName} data-toggle="dropdown" onclick={this.props.onclick}>
-        {this.getButtonContent()}
+      <button className={'Dropdown-toggle ' + this.attrs.buttonClassName} data-toggle="dropdown" onclick={this.attrs.onclick}>
+        {this.getButtonContent(children)}
       </button>
     );
   }
@@ -104,15 +104,15 @@ export default class Dropdown extends Component {
    * @return {*}
    * @protected
    */
-  getButtonContent() {
+  getButtonContent(children) {
     return [
-      this.props.icon ? icon(this.props.icon, { className: 'Button-icon' }) : '',
-      <span className="Button-label">{this.props.label}</span>,
-      this.props.caretIcon ? icon(this.props.caretIcon, { className: 'Button-caret' }) : '',
+      this.attrs.icon ? icon(this.attrs.icon, { className: 'Button-icon' }) : '',
+      <span className="Button-label">{this.attrs.label}</span>,
+      this.attrs.caretIcon ? icon(this.attrs.caretIcon, { className: 'Button-caret' }) : '',
     ];
   }
 
   getMenu(items) {
-    return <ul className={'Dropdown-menu dropdown-menu ' + this.props.menuClassName}>{items}</ul>;
+    return <ul className={'Dropdown-menu dropdown-menu ' + this.attrs.menuClassName}>{items}</ul>;
   }
 }

js/src/common/components/FieldSet.js

@@ -11,11 +11,11 @@ import listItems from '../helpers/listItems';
  * The children should be an array of items to show in the fieldset.
  */
 export default class FieldSet extends Component {
-  view() {
+  view(vnode) {
     return (
-      <fieldset className={this.props.className}>
-        <legend>{this.props.label}</legend>
-        <ul>{listItems(this.props.children)}</ul>
+      <fieldset className={this.attrs.className}>
+        <legend>{this.attrs.label}</legend>
+        <ul>{listItems(vnode.children)}</ul>
       </fieldset>
     );
   }

js/src/common/components/GroupBadge.js

@@ -1,16 +1,16 @@
 import Badge from './Badge';
 
 export default class GroupBadge extends Badge {
-  static initProps(props) {
-    super.initProps(props);
+  static initAttrs(attrs) {
+    super.initAttrs(attrs);
 
-    if (props.group) {
-      props.icon = props.group.icon();
-      props.style = { backgroundColor: props.group.color() };
-      props.label = typeof props.label === 'undefined' ? props.group.nameSingular() : props.label;
-      props.type = 'group--' + props.group.id();
+    if (attrs.group) {
+      attrs.icon = attrs.group.icon();
+      attrs.style = { backgroundColor: attrs.group.color() };
+      attrs.label = typeof attrs.label === 'undefined' ? attrs.group.nameSingular() : attrs.label;
+      attrs.type = 'group--' + attrs.group.id();
 
-      delete props.group;
+      delete attrs.group;
     }
   }
 }

js/src/common/components/LinkButton.js

@@ -3,9 +3,9 @@ import Button from './Button';
 /**
  * The `LinkButton` component defines a `Button` which links to a route.
  *
- * ### Props
+ * ### Attrs
  *
- * All of the props accepted by `Button`, plus:
+ * All of the attrs accepted by `Button`, plus:
  *
  * - `active` Whether or not the page that this button links to is currently
  *   active.
@@ -13,26 +13,28 @@ import Button from './Button';
  *   the `active` prop will automatically be set to true.
  */
 export default class LinkButton extends Button {
-  static initProps(props) {
-    props.active = this.isActive(props);
-    props.config = props.config || m.route;
+  static initAttrs(attrs) {
+    super.initAttrs(attrs);
+
+    attrs.active = this.isActive(attrs);
   }
 
-  view() {
-    const vdom = super.view();
+  view(vnode) {
+    const vdom = super.view(vnode);
 
-    vdom.tag = 'a';
+    vdom.tag = m.route.Link;
+    vdom.attrs.active = String(vdom.attrs.active);
 
     return vdom;
   }
 
   /**
-   * Determine whether a component with the given props is 'active'.
+   * Determine whether a component with the given attrs is 'active'.
    *
-   * @param {Object} props
+   * @param {Object} attrs
    * @return {Boolean}
    */
-  static isActive(props) {
-    return typeof props.active !== 'undefined' ? props.active : m.route() === props.href;
+  static isActive(attrs) {
+    return typeof attrs.active !== 'undefined' ? attrs.active : m.route.get() === attrs.href;
   }
 }

js/src/common/components/LoadingIndicator.js

@@ -2,16 +2,17 @@ import Component from '../Component';
 import { Spinner } from 'spin.js';
 
 /**
- * The `LoadingIndicator` component displays a loading spinner with spin.js. It
- * may have the following special props:
+ * The `LoadingIndicator` component displays a loading spinner with spin.js.
+ *
+ * ### Attrs
  *
  * - `size` The spin.js size preset to use. Defaults to 'small'.
  *
- * All other props will be assigned as attributes on the element.
+ * All other attrs will be assigned as attributes on the DOM element.
  */
 export default class LoadingIndicator extends Component {
   view() {
-    const attrs = Object.assign({}, this.props);
+    const attrs = Object.assign({}, this.attrs);
 
     attrs.className = 'LoadingIndicator ' + (attrs.className || '');
     delete attrs.size;
@@ -19,12 +20,12 @@ export default class LoadingIndicator extends Component {
     return <div {...attrs}>{m.trust('&nbsp;')}</div>;
   }
 
-  config(isInitialized) {
-    if (isInitialized) return;
+  oncreate(vnode) {
+    super.oncreate(vnode);
 
     const options = { zIndex: 'auto', color: this.$().css('color') };
 
-    switch (this.props.size) {
+    switch (this.attrs.size) {
       case 'large':
         Object.assign(options, { lines: 10, length: 8, width: 4, radius: 8 });
         break;

js/src/common/components/Modal.js

@@ -14,23 +14,21 @@ export default class Modal extends Component {
    */
   static isDismissible = true;
 
-  init() {
   /**
    * Attributes for an alert component to show below the header.
    *
    * @type {object}
    */
-    this.alertAttrs = null;
+  alertAttrs = null;
+
+  oncreate(vnode) {
+    super.oncreate(vnode);
+
+    this.attrs.onshow(() => this.onready());
   }
 
-  config(isInitialized, context) {
-    if (isInitialized) return;
-
-    this.props.onshow(() => this.onready());
-
-    context.onunload = () => {
-      this.props.onhide();
-    };
+  onremove() {
+    this.attrs.onhide();
   }
 
   view() {
@@ -109,7 +107,7 @@ export default class Modal extends Component {
    * Hide the modal.
    */
   hide() {
-    this.props.onhide();
+    this.attrs.onhide();
   }
 
   /**

js/src/common/components/ModalManager.js

@@ -6,12 +6,8 @@ import Component from '../Component';
  * overwrite the previous one.
  */
 export default class ModalManager extends Component {
-  init() {
-    this.state = this.props.state;
-  }
-
   view() {
-    const modal = this.state.modal;
+    const modal = this.attrs.state.modal;
 
     return (
       <div className="ModalManager modal fade">
@@ -20,22 +16,17 @@ export default class ModalManager extends Component {
     );
   }
 
-  config(isInitialized, context) {
-    if (isInitialized) return;
-
-    // Since this component is 'above' the content of the page (that is, it is a
-    // part of the global UI that persists between routes), we will flag the DOM
-    // to be retained across route changes.
-    context.retain = true;
+  oncreate(vnode) {
+    super.oncreate(vnode);
 
     // Ensure the modal state is notified about a closed modal, even when the
     // DOM-based Bootstrap JavaScript code triggered the closing of the modal,
     // e.g. via ESC key or a click on the modal backdrop.
-    this.$().on('hidden.bs.modal', this.state.close.bind(this.state));
+    this.$().on('hidden.bs.modal', this.attrs.state.close.bind(this.attrs.state));
   }
 
   animateShow(readyCallback) {
-    const dismissible = !!this.state.modal.componentClass.isDismissible;
+    const dismissible = !!this.attrs.state.modal.componentClass.isDismissible;
 
     this.$()
       .one('shown.bs.modal', readyCallback)

js/src/common/components/Navigation.js

@@ -11,7 +11,7 @@ import LinkButton from './LinkButton';
  * If the app has a pane, it will also include a 'pin' button which toggles the
  * pinned state of the pane.
  *
- * Accepts the following props:
+ * Accepts the following attrs:
  *
  * - `className` The name of a class to set on the root element.
  * - `drawer` Whether or not to show a button to toggle the app's drawer if
@@ -23,7 +23,7 @@ export default class Navigation extends Component {
 
     return (
       <div
-        className={'Navigation ButtonGroup ' + (this.props.className || '')}
+        className={'Navigation ButtonGroup ' + (this.attrs.className || '')}
         onmouseenter={pane && pane.show.bind(pane)}
         onmouseleave={pane && pane.onmouseleave.bind(pane)}
       >
@@ -32,13 +32,6 @@ export default class Navigation extends Component {
     );
   }
 
-  config(isInitialized, context) {
-    // Since this component is 'above' the content of the page (that is, it is a
-    // part of the global UI that persists between routes), we will flag the DOM
-    // to be retained across route changes.
-    context.retain = true;
-  }
-
   /**
    * Get the back button.
    *
@@ -54,7 +47,6 @@ export default class Navigation extends Component {
       href: history.backUrl(),
       icon: 'fas fa-chevron-left',
       title: previous.title,
-      config: () => {},
       onclick: (e) => {
         if (e.shiftKey || e.ctrlKey || e.metaKey || e.which === 2) return;
         e.preventDefault();
@@ -88,7 +80,7 @@ export default class Navigation extends Component {
    * @protected
    */
   getDrawerButton() {
-    if (!this.props.drawer) return '';
+    if (!this.attrs.drawer) return '';
 
     const { drawer } = app;
     const user = app.session.user;

js/src/common/components/Page.js

@@ -7,10 +7,14 @@ import PageState from '../states/PageState';
  * @abstract
  */
 export default class Page extends Component {
-  init() {
+  oninit(vnode) {
+    super.oninit(vnode);
+
     app.previous = app.current;
     app.current = new PageState(this.constructor);
 
+    this.onNewRoute();
+
     app.drawer.hide();
     app.modal.close();
 
@@ -22,13 +26,27 @@ export default class Page extends Component {
     this.bodyClass = '';
   }
 
-  config(isInitialized, context) {
-    if (isInitialized) return;
+  /**
+   * A collections of actions to run when the route changes.
+   * This is extracted here, and not hardcoded in oninit, as oninit is not called
+   * when a different route is handled by the same component, but we still need to
+   * adjust the current route name.
+   */
+  onNewRoute() {
+    app.current.set('routeName', this.attrs.routeName);
+  }
+
+  oncreate(vnode) {
+    super.oncreate(vnode);
 
     if (this.bodyClass) {
       $('#app').addClass(this.bodyClass);
+    }
+  }
 
-      context.onunload = () => $('#app').removeClass(this.bodyClass);
+  onremove() {
+    if (this.bodyClass) {
+      $('#app').removeClass(this.bodyClass);
     }
   }
 }

js/src/common/components/Placeholder.js

@@ -4,7 +4,7 @@ import Component from '../Component';
  * The `Placeholder` component displays a muted text with some call to action,
  * usually used as an empty state.
  *
- * ### Props
+ * ### Attrs
  *
  * - `text`
  */
@@ -12,7 +12,7 @@ export default class Placeholder extends Component {
   view() {
     return (
       <div className="Placeholder">
-        <p>{this.props.text}</p>
+        <p>{this.attrs.text}</p>
       </div>
     );
   }

js/src/common/components/RequestErrorModal.js

@@ -6,11 +6,11 @@ export default class RequestErrorModal extends Modal {
   }
 
   title() {
-    return this.props.error.xhr ? `${this.props.error.xhr.status} ${this.props.error.xhr.statusText}` : '';
+    return this.attrs.error.xhr ? `${this.attrs.error.xhr.status} ${this.attrs.error.xhr.statusText}` : '';
   }
 
   content() {
-    const { error, formattedError } = this.props;
+    const { error, formattedError } = this.attrs;
 
     let responseText;
 
@@ -31,7 +31,7 @@ export default class RequestErrorModal extends Modal {
     return (
       <div className="Modal-body">
         <pre>
-          {this.props.error.options.method} {this.props.error.options.url}
+          {this.attrs.error.options.method} {this.attrs.error.options.url}
           <br />
           <br />
           {responseText}

js/src/common/components/Select.js

@@ -1,9 +1,10 @@
 import Component from '../Component';
 import icon from '../helpers/icon';
+import withAttr from '../utils/withAttr';
 
 /**
  * The `Select` component displays a <select> input, surrounded with some extra
- * elements for styling. It accepts the following props:
+ * elements for styling. It accepts the following attrs:
  *
  * - `options` A map of option values to labels.
  * - `onchange` A callback to run when the selected value is changed.
@@ -12,13 +13,13 @@ import icon from '../helpers/icon';
  */
 export default class Select extends Component {
   view() {
-    const { options, onchange, value, disabled } = this.props;
+    const { options, onchange, value, disabled } = this.attrs;
 
     return (
       <span className="Select">
         <select
           className="Select-input FormControl"
-          onchange={onchange ? m.withAttr('value', onchange.bind(this)) : undefined}
+          onchange={onchange ? withAttr('value', onchange.bind(this)) : undefined}
           value={value}
           disabled={disabled}
         >

js/src/common/components/SelectDropdown.js

@@ -1,31 +1,49 @@
 import Dropdown from './Dropdown';
 import icon from '../helpers/icon';
 
+/**
+ * Determines via a vnode is currently "active".
+ * Due to changes in Mithril 2, attrs will not be instantiated until AFTER view()
+ * is initially called on the parent component, so we can not always depend on the
+ * active attr to determine which element should be displayed as the "active child".
+ *
+ * This is a temporary patch, and as so, is not exported / placed in utils.
+ */
+function isActive(vnode) {
+  const tag = vnode.tag;
+
+  if ('initAttrs' in tag) {
+    tag.initAttrs(vnode.attrs);
+  }
+
+  return 'isActive' in tag ? tag.isActive(vnode.attrs) : vnode.attrs.active;
+}
+
 /**
  * The `SelectDropdown` component is the same as a `Dropdown`, except the toggle
  * button's label is set as the label of the first child which has a truthy
  * `active` prop.
  *
- * ### Props
+ * ### Attrs
  *
  * - `caretIcon`
  * - `defaultLabel`
  */
 export default class SelectDropdown extends Dropdown {
-  static initProps(props) {
-    props.caretIcon = typeof props.caretIcon !== 'undefined' ? props.caretIcon : 'fas fa-sort';
+  static initAttrs(attrs) {
+    attrs.caretIcon = typeof attrs.caretIcon !== 'undefined' ? attrs.caretIcon : 'fas fa-sort';
 
-    super.initProps(props);
+    super.initAttrs(attrs);
 
-    props.className += ' Dropdown--select';
+    attrs.className += ' Dropdown--select';
   }
 
-  getButtonContent() {
-    const activeChild = this.props.children.filter((child) => child.props.active)[0];
-    let label = (activeChild && activeChild.props.children) || this.props.defaultLabel;
+  getButtonContent(children) {
+    const activeChild = children.find(isActive);
+    let label = (activeChild && activeChild.children) || this.attrs.defaultLabel;
 
     if (label instanceof Array) label = label[0];
 
-    return [<span className="Button-label">{label}</span>, icon(this.props.caretIcon, { className: 'Button-caret' })];
+    return [<span className="Button-label">{label}</span>, icon(this.attrs.caretIcon, { className: 'Button-caret' })];
   }
 }

js/src/common/components/SplitDropdown.js

@@ -7,25 +7,25 @@ import icon from '../helpers/icon';
  * is displayed as its own button prior to the toggle button.
  */
 export default class SplitDropdown extends Dropdown {
-  static initProps(props) {
-    super.initProps(props);
+  static initAttrs(attrs) {
+    super.initAttrs(attrs);
 
-    props.className += ' Dropdown--split';
-    props.menuClassName += ' Dropdown-menu--right';
+    attrs.className += ' Dropdown--split';
+    attrs.menuClassName += ' Dropdown-menu--right';
   }
 
-  getButton() {
-    // Make a copy of the props of the first child component. We will assign
-    // these props to a new button, so that it has exactly the same behaviour as
+  getButton(children) {
+    // Make a copy of the attrs of the first child component. We will assign
+    // these attrs to a new button, so that it has exactly the same behaviour as
     // the first child.
-    const firstChild = this.getFirstChild();
-    const buttonProps = Object.assign({}, firstChild.props);
-    buttonProps.className = (buttonProps.className || '') + ' SplitDropdown-button Button ' + this.props.buttonClassName;
+    const firstChild = this.getFirstChild(children);
+    const buttonAttrs = Object.assign({}, firstChild.attrs);
+    buttonAttrs.className = (buttonAttrs.className || '') + ' SplitDropdown-button Button ' + this.attrs.buttonClassName;
 
     return [
-      Button.component(buttonProps),
-      <button className={'Dropdown-toggle Button Button--icon ' + this.props.buttonClassName} data-toggle="dropdown">
-        {icon(this.props.icon, { className: 'Button-icon' })}
+      Button.component(buttonAttrs, firstChild.children),
+      <button className={'Dropdown-toggle Button Button--icon ' + this.attrs.buttonClassName} data-toggle="dropdown">
+        {icon(this.attrs.icon, { className: 'Button-icon' })}
         {icon('fas fa-caret-down', { className: 'Button-caret' })}
       </button>,
     ];
@@ -38,8 +38,8 @@ export default class SplitDropdown extends Dropdown {
    * @return {*}
    * @protected
    */
-  getFirstChild() {
-    let firstChild = this.props.children;
+  getFirstChild(children) {
+    let firstChild = children;
 
     while (firstChild instanceof Array) firstChild = firstChild[0];
 

js/src/common/components/Switch.js

@@ -5,13 +5,13 @@ import Checkbox from './Checkbox';
  * a tick/cross one.
  */
 export default class Switch extends Checkbox {
-  static initProps(props) {
-    super.initProps(props);
+  static initAttrs(attrs) {
+    super.initAttrs(attrs);
 
-    props.className = (props.className || '') + ' Checkbox--switch';
+    attrs.className = (attrs.className || '') + ' Checkbox--switch';
   }
 
   getDisplay() {
-    return this.props.loading ? super.getDisplay() : '';
+    return this.attrs.loading ? super.getDisplay() : '';
   }
 }

js/src/common/helpers/listItems.js

@@ -2,14 +2,14 @@ import Separator from '../components/Separator';
 import classList from '../utils/classList';
 
 function isSeparator(item) {
-  return item && item.component === Separator;
+  return item.tag === Separator;
 }
 
 function withoutUnnecessarySeparators(items) {
   const newItems = [];
   let prevItem;
 
-  items.forEach((item, i) => {
+  items.filter(Boolean).forEach((item, i) => {
     if (!isSeparator(item) || (prevItem && !isSeparator(prevItem) && i !== items.length - 1)) {
       prevItem = item;
       newItems.push(item);
@@ -30,21 +30,27 @@ export default function listItems(items) {
   if (!(items instanceof Array)) items = [items];
 
   return withoutUnnecessarySeparators(items).map((item) => {
-    const isListItem = item.component && item.component.isListItem;
-    const active = item.component && item.component.isActive && item.component.isActive(item.props);
-    const className = item.props ? item.props.itemClassName : item.itemClassName;
+    const isListItem = item.tag && item.tag.isListItem;
+    const active = item.tag && item.tag.isActive && item.tag.isActive(item.attrs);
+    const className = (item.attrs && item.attrs.itemClassName) || item.itemClassName;
 
     if (isListItem) {
       item.attrs = item.attrs || {};
       item.attrs.key = item.attrs.key || item.itemName;
+      item.key = item.attrs.key;
     }
 
-    return isListItem ? (
+    const node = isListItem ? (
       item
     ) : (
-      <li className={classList([item.itemName ? 'item-' + item.itemName : '', className, active ? 'active' : ''])} key={item.itemName}>
+      <li
+        className={classList([className, item.itemName && `item-${item.itemName}`, active && 'active'])}
+        key={(item.attrs && item.attrs.key) || item.itemName}
+      >
         {item}
       </li>
     );
+
+    return node;
   });
 }

js/src/common/states/AlertManagerState.js

@@ -13,7 +13,21 @@ export default class AlertManagerState {
   /**
    * Show an Alert in the alerts area.
    */
-  show(attrs, componentClass = Alert) {
+  show(arg1, arg2, arg3) {
+    let componentClass = Alert;
+    let attrs = {};
+    let children;
+    if (arguments.length == 1) {
+      children = arg1;
+    } else if (arguments.length == 2) {
+      attrs = arg1;
+      children = arg2;
+    } else if (arguments.length == 3) {
+      componentClass = arg1;
+      attrs = arg2;
+      children = arg3;
+    }
+
     // Breaking Change Compliance Warning, Remove in Beta 15.
     // This is applied to the first argument (attrs) because previously, the alert was passed as the first argument.
     if (attrs === Alert || attrs instanceof Alert) {
@@ -22,7 +36,7 @@ export default class AlertManagerState {
       throw new Error('The AlertManager can only show Alerts. Whichever extension triggered this alert should be updated to comply with beta 14.');
     }
     // End Change Compliance Warning, Remove in Beta 15
-    this.activeAlerts[++this.alertId] = { attrs, componentClass };
+    this.activeAlerts[++this.alertId] = { children, attrs, componentClass };
     m.redraw();
 
     return this.alertId;

js/src/common/states/ModalManagerState.js

@@ -32,7 +32,7 @@ export default class ModalManagerState {
 
     this.modal = { componentClass, attrs };
 
-    m.redraw(true);
+    m.redraw.sync();
   }
 
   /**
@@ -50,7 +50,7 @@ export default class ModalManagerState {
     // ahead.
     this.closeTimeout = setTimeout(() => {
       this.modal = null;
-      m.lazyRedraw();
+      m.redraw();
     });
   }
 }

js/src/common/utils/SubtreeRetainer.js

@@ -1,20 +1,25 @@
 /**
- * The `SubtreeRetainer` class represents a Mithril virtual DOM subtree. It
- * keeps track of a number of pieces of data, allowing the subtree to be
- * retained if none of them have changed.
+ * The `SubtreeRetainer` class keeps track of a number of pieces of data,
+ * comparing the values of these pieces at every iteration.
+ *
+ * This is useful for preventing redraws to relatively static (or huge)
+ * components whose VDOM only depends on very few values, when none of them
+ * have changed.
  *
  * @example
- * // constructor
+ * // Check two callbacks for changes on each update
  * this.subtree = new SubtreeRetainer(
- *   () => this.props.post.freshness,
+ *   () => this.attrs.post.freshness,
  *   () => this.showing
  * );
- * this.subtree.check(() => this.props.user.freshness);
  *
- * // view
- * this.subtree.retain() || 'expensive expression'
+ * // Add more callbacks to be checked for updates
+ * this.subtree.check(() => this.attrs.user.freshness);
  *
- * @see https://lhorie.github.io/mithril/mithril.html#persisting-dom-elements-across-route-changes
+ * // In a component's onbeforeupdate() method:
+ * return this.subtree.needsRebuild()
+ *
+ * @see https://mithril.js.org/lifecycle-methods.html#onbeforeupdate
  */
 export default class SubtreeRetainer {
   /**
@@ -26,13 +31,13 @@ export default class SubtreeRetainer {
   }
 
   /**
-   * Return a virtual DOM directive that will retain a subtree if no data has
-   * changed since the last check.
+   * Return whether any data has changed since the last check.
+   * If so, Mithril needs to re-diff the vnode and its children.
    *
-   * @return {Object|false}
+   * @return {boolean}
    * @public
    */
-  retain() {
+  needsRebuild() {
     let needsRebuild = false;
 
     this.callbacks.forEach((callback, i) => {
@@ -44,7 +49,7 @@ export default class SubtreeRetainer {
       }
     });
 
-    return needsRebuild ? false : { subtree: 'retain' };
+    return needsRebuild;
   }
 
   /**

js/src/common/utils/extractText.js

@@ -8,7 +8,7 @@ export default function extractText(vdom) {
   if (vdom instanceof Array) {
     return vdom.map((element) => extractText(element)).join('');
   } else if (typeof vdom === 'object' && vdom !== null) {
-    return extractText(vdom.children);
+    return vdom.children ? extractText(vdom.children) : vdom.text;
   } else {
     return vdom;
   }

js/src/common/utils/mapRoutes.js

@@ -2,7 +2,7 @@
  * The `mapRoutes` utility converts a map of named application routes into a
  * format that can be understood by Mithril.
  *
- * @see https://lhorie.github.io/mithril/mithril.route.html#defining-routes
+ * @see https://mithril.js.org/route.html#signature
  * @param {Object} routes
  * @param {String} [basePath]
  * @return {Object}
@@ -13,9 +13,11 @@ export default function mapRoutes(routes, basePath = '') {
   for (const key in routes) {
     const route = routes[key];
 
-    if (route.component) route.component.props.routeName = key;
-
-    map[basePath + route.path] = route.component;
+    map[basePath + route.path] = {
+      render() {
+        return m(route.component, { routeName: key });
+      },
+    };
   }
 
   return map;

js/src/common/utils/patchMithril.js

@@ -1,27 +1,60 @@
-import Component from '../Component';
+import Stream from 'mithril/stream';
+import extract from './extract';
 
 export default function patchMithril(global) {
-  const mo = global.m;
+  const defaultMithril = global.m;
 
-  const m = function (comp, ...args) {
-    if (comp.prototype && comp.prototype instanceof Component) {
-      let children = args.slice(1);
-      if (children.length === 1 && Array.isArray(children[0])) {
-        children = children[0];
+  /**
+   * If the href URL of the link is the same as the current page path
+   * we will not add a new entry to the browser history.
+   *
+   * This allows us to still refresh the Page component
+   * without adding endless history entries.
+   *
+   * We also add the `force` attribute that adds a custom state key
+   * for when you want to force a complete refresh of the Page
+   */
+  const defaultLinkView = defaultMithril.route.Link.view;
+  const modifiedLink = {
+    view: function (vnode) {
+      let { href, options = {} } = vnode.attrs;
+
+      if (href === m.route.get()) {
+        if (!('replace' in options)) options.replace = true;
       }
 
-      return comp.component(args[0], children);
+      if (extract(vnode.attrs, 'force')) {
+        if (!('state' in options)) options.state = {};
+        if (!('key' in options.state)) options.state.key = Date.now();
       }
 
-    const node = mo.apply(this, arguments);
+      vnode.attrs.options = options;
 
+      return defaultLinkView(vnode);
+    },
+  };
+
+  const modifiedMithril = function (comp, ...args) {
+    const node = defaultMithril.apply(this, arguments);
+
+    if (!node.attrs) node.attrs = {};
+
+    // Allows the use of the bidi attr.
     if (node.attrs.bidi) {
-      m.bidi(node, node.attrs.bidi);
+      modifiedMithril.bidi(node, node.attrs.bidi);
     }
 
+    // Allows us to use a "route" attr on links, which will automatically convert the link to one which
+    // supports linking to other pages in the SPA without refreshing the document.
     if (node.attrs.route) {
       node.attrs.href = node.attrs.route;
-      node.attrs.config = m.route;
+      node.tag = modifiedLink;
+
+      // For some reason, m.route.Link does not like vnode.text, so if present, we
+      // need to convert it to text vnodes and store it in children.
+      if (node.text) {
+        node.children = { tag: '#', children: node.text };
+      }
 
       delete node.attrs.route;
     }
@@ -29,17 +62,11 @@ export default function patchMithril(global) {
     return node;
   };
 
-  Object.keys(mo).forEach((key) => (m[key] = mo[key]));
+  Object.keys(defaultMithril).forEach((key) => (modifiedMithril[key] = defaultMithril[key]));
 
-  /**
-   * Redraw only if not in the middle of a computation (e.g. a route change).
-   *
-   * @return {void}
-   */
-  m.lazyRedraw = function () {
-    m.startComputation();
-    m.endComputation();
-  };
+  modifiedMithril.stream = Stream;
 
-  global.m = m;
+  modifiedMithril.route.Link = modifiedLink;
+
+  global.m = modifiedMithril;
 }

js/src/common/utils/setRouteWithForcedRefresh.ts

@@ -0,0 +1,15 @@
+import Mithril from 'mithril';
+
+/**
+ * Mithril 2 does not completely rerender the page if a route change leads to the same route
+ * (or the same component handling a different route). This util calls m.route.set, forcing a reonit.
+ *
+ * @see https://mithril.js.org/route.html#key-parameter
+ */
+export default function setRouteWithForcedRefresh(route: string, params = null, options: Mithril.RouteOptions = {}) {
+  const newOptions = { ...options };
+  newOptions.state = newOptions.state || {};
+  newOptions.state.key = Date.now();
+
+  m.route.set(route, params, newOptions);
+}

js/src/common/utils/withAttr.ts

@@ -0,0 +1,15 @@
+/**
+ * An event handler factory that makes it simpler to implement data binding
+ * for component event listeners.
+ *
+ * The handler created by this factory passes the DOM element's attribute
+ * identified by the first argument to the callback (usually a bidirectional
+ * Mithril stream: https://mithril.js.org/stream.html#bidirectional-bindings).
+ *
+ * Replaces m.withAttr for Mithril 2.0.
+ * @see https://mithril.js.org/archive/v0.2.5/mithril.withAttr.html
+ */
+export default (key: string, cb: Function) =>
+  function (this: Element) {
+    cb(this.getAttribute(key) || this[key]);
+  };

js/src/forum/ForumApplication.js

@@ -115,15 +115,15 @@ export default class ForumApplication extends Application {
     this.routes[defaultAction].path = '/';
     this.history.push(defaultAction, this.translator.trans('core.forum.header.back_to_index_tooltip'), '/');
 
-    m.mount(document.getElementById('app-navigation'), Navigation.component({ className: 'App-backControl', drawer: true }));
-    m.mount(document.getElementById('header-navigation'), Navigation.component());
-    m.mount(document.getElementById('header-primary'), HeaderPrimary.component());
-    m.mount(document.getElementById('header-secondary'), HeaderSecondary.component());
-    m.mount(document.getElementById('composer'), Composer.component({ state: this.composer }));
+    m.mount(document.getElementById('app-navigation'), { view: () => Navigation.component({ className: 'App-backControl', drawer: true }) });
+    m.mount(document.getElementById('header-navigation'), Navigation);
+    m.mount(document.getElementById('header-primary'), HeaderPrimary);
+    m.mount(document.getElementById('header-secondary'), HeaderSecondary);
+    m.mount(document.getElementById('composer'), { view: () => Composer.component({ state: this.composer }) });
 
     this.pane = new Pane(document.getElementById('app'));
 
-    m.route.mode = 'pathname';
+    m.route.prefix = '';
     super.mount(this.forum.attribute('basePath'));
 
     alertEmailConfirmation(this);
@@ -161,8 +161,8 @@ export default class ForumApplication extends Application {
    * will be reloaded. Otherwise, a SignUpModal will be opened, prefilled
    * with the provided details.
    *
-   * @param {Object} payload A dictionary of props to pass into the sign up
-   *     modal. A truthy `loggedIn` prop indicates that the user has logged
+   * @param {Object} payload A dictionary of attrs to pass into the sign up
+   *     modal. A truthy `loggedIn` attr indicates that the user has logged
    *     in, and thus the page is reloaded.
    * @public
    */

js/src/forum/compat.js

@@ -3,7 +3,6 @@ import compat from '../common/compat';
 import PostControls from './utils/PostControls';
 import KeyboardNavigatable from './utils/KeyboardNavigatable';
 import slidable from './utils/slidable';
-import affixSidebar from './utils/affixSidebar';
 import History from './utils/History';
 import DiscussionControls from './utils/DiscussionControls';
 import alertEmailConfirmation from './utils/alertEmailConfirmation';
@@ -15,6 +14,7 @@ import GlobalSearchState from './states/GlobalSearchState';
 import NotificationListState from './states/NotificationListState';
 import PostStreamState from './states/PostStreamState';
 import SearchState from './states/SearchState';
+import AffixedSidebar from './components/AffixedSidebar';
 import DiscussionPage from './components/DiscussionPage';
 import LogInModal from './components/LogInModal';
 import ComposerBody from './components/ComposerBody';
@@ -61,6 +61,7 @@ import NotificationList from './components/NotificationList';
 import WelcomeHero from './components/WelcomeHero';
 import SignUpModal from './components/SignUpModal';
 import CommentPost from './components/CommentPost';
+import ComposerPostPreview from './components/ComposerPostPreview';
 import ReplyComposer from './components/ReplyComposer';
 import NotificationsPage from './components/NotificationsPage';
 import PostStreamScrubber from './components/PostStreamScrubber';
@@ -77,7 +78,6 @@ export default Object.assign(compat, {
   'utils/PostControls': PostControls,
   'utils/KeyboardNavigatable': KeyboardNavigatable,
   'utils/slidable': slidable,
-  'utils/affixSidebar': affixSidebar,
   'utils/History': History,
   'utils/DiscussionControls': DiscussionControls,
   'utils/alertEmailConfirmation': alertEmailConfirmation,
@@ -89,6 +89,7 @@ export default Object.assign(compat, {
   'states/NotificationListState': NotificationListState,
   'states/PostStreamState': PostStreamState,
   'states/SearchState': SearchState,
+  'components/AffixedSidebar': AffixedSidebar,
   'components/DiscussionPage': DiscussionPage,
   'components/LogInModal': LogInModal,
   'components/ComposerBody': ComposerBody,
@@ -135,6 +136,7 @@ export default Object.assign(compat, {
   'components/WelcomeHero': WelcomeHero,
   'components/SignUpModal': SignUpModal,
   'components/CommentPost': CommentPost,
+  'components/ComposerPostPreview': ComposerPostPreview,
   'components/ReplyComposer': ReplyComposer,
   'components/NotificationsPage': NotificationsPage,
   'components/PostStreamScrubber': PostStreamScrubber,

js/src/forum/components/AffixedSidebar.js

@@ -0,0 +1,51 @@
+import Component from '../../common/Component';
+
+/**
+ * The `AffixedSidebar` component uses Bootstrap's "affix" plugin to keep a
+ * sidebar navigation at the top of the viewport when scrolling.
+ *
+ * ### Children
+ *
+ * The component must wrap an element that itself wraps an <ul> element, which
+ * will be "affixed".
+ *
+ * @see https://getbootstrap.com/docs/3.4/javascript/#affix
+ */
+export default class AffixedSidebar extends Component {
+  view(vnode) {
+    return vnode.children[0];
+  }
+
+  oncreate(vnode) {
+    super.oncreate(vnode);
+
+    // Register the affix plugin to execute on every window resize (and trigger)
+    this.boundOnresize = this.onresize.bind(this);
+    $(window).on('resize', this.boundOnresize).resize();
+  }
+
+  onremove() {
+    $(window).off('resize', this.boundOnresize);
+  }
+
+  onresize() {
+    const $sidebar = this.$();
+    const $header = $('#header');
+    const $footer = $('#footer');
+    const $affixElement = $sidebar.find('> ul');
+
+    $(window).off('.affix');
+    $affixElement.removeClass('affix affix-top affix-bottom').removeData('bs.affix');
+
+    // Don't affix the sidebar if it is taller than the viewport (otherwise
+    // there would be no way to scroll through its content).
+    if ($sidebar.outerHeight(true) > $(window).height() - $header.outerHeight(true)) return;
+
+    $affixElement.affix({
+      offset: {
+        top: () => $sidebar.offset().top - $header.outerHeight(true) - parseInt($sidebar.css('margin-top'), 10),
+        bottom: () => (this.bottom = $footer.outerHeight(true)),
+      },
+    });
+  }
+}

js/src/forum/components/AvatarEditor.js

@@ -3,6 +3,7 @@ import avatar from '../../common/helpers/avatar';
 import icon from '../../common/helpers/icon';
 import listItems from '../../common/helpers/listItems';
 import ItemList from '../../common/utils/ItemList';
+import classList from '../../common/utils/classList';
 import Button from '../../common/components/Button';
 import LoadingIndicator from '../../common/components/LoadingIndicator';
 
@@ -10,13 +11,15 @@ import LoadingIndicator from '../../common/components/LoadingIndicator';
  * The `AvatarEditor` component displays a user's avatar along with a dropdown
  * menu which allows the user to upload/remove the avatar.
  *
- * ### Props
+ * ### Attrs
  *
  * - `className`
  * - `user`
  */
 export default class AvatarEditor extends Component {
-  init() {
+  oninit(vnode) {
+    super.oninit(vnode);
+
     /**
      * Whether or not an avatar upload is in progress.
      *
@@ -32,17 +35,11 @@ export default class AvatarEditor extends Component {
     this.isDraggedOver = false;
   }
 
-  static initProps(props) {
-    super.initProps(props);
-
-    props.className = props.className || '';
-  }
-
   view() {
-    const user = this.props.user;
+    const user = this.attrs.user;
 
     return (
-      <div className={'AvatarEditor Dropdown ' + this.props.className + (this.loading ? ' loading' : '') + (this.isDraggedOver ? ' dragover' : '')}>
+      <div className={classList(['AvatarEditor', 'Dropdown', this.attrs.className, this.loading && 'loading', this.isDraggedOver && 'dragover'])}>
         {avatar(user)}
         <a
           className={user.avatarUrl() ? 'Dropdown-toggle' : 'Dropdown-toggle AvatarEditor--noAvatar'}
@@ -55,7 +52,7 @@ export default class AvatarEditor extends Component {
           ondragend={this.disableDragover.bind(this)}
           ondrop={this.dropUpload.bind(this)}
         >
-          {this.loading ? LoadingIndicator.component() : user.avatarUrl() ? icon('fas fa-pencil-alt') : icon('fas fa-plus-circle')}
+          {this.loading ? <LoadingIndicator /> : user.avatarUrl() ? icon('fas fa-pencil-alt') : icon('fas fa-plus-circle')}
         </a>
         <ul className="Dropdown-menu Menu">{listItems(this.controlItems().toArray())}</ul>
       </div>
@@ -72,20 +69,16 @@ export default class AvatarEditor extends Component {
 
     items.add(
       'upload',
-      Button.component({
-        icon: 'fas fa-upload',
-        children: app.translator.trans('core.forum.user.avatar_upload_button'),
-        onclick: this.openPicker.bind(this),
-      })
+      <Button icon="fas fa-upload" onclick={this.openPicker.bind(this)}>
+        {app.translator.trans('core.forum.user.avatar_upload_button')}
+      </Button>
     );
 
     items.add(
       'remove',
-      Button.component({
-        icon: 'fas fa-times',
-        children: app.translator.trans('core.forum.user.avatar_remove_button'),
-        onclick: this.remove.bind(this),
-      })
+      <Button icon="fas fa-times" onclick={this.remove.bind(this)}>
+        {app.translator.trans('core.forum.user.avatar_remove_button')}
+      </Button>
     );
 
     return items;
@@ -134,7 +127,7 @@ export default class AvatarEditor extends Component {
    * @param {Event} e
    */
   quickUpload(e) {
-    if (!this.props.user.avatarUrl()) {
+    if (!this.attrs.user.avatarUrl()) {
       e.preventDefault();
       e.stopPropagation();
       this.openPicker();
@@ -149,7 +142,6 @@ export default class AvatarEditor extends Component {
 
     // Create a hidden HTML input element and click on it so the user can select
     // an avatar file. Once they have, we will upload it via the API.
-    const user = this.props.user;
     const $input = $('<input type="file">');
 
     $input
@@ -169,7 +161,7 @@ export default class AvatarEditor extends Component {
   upload(file) {
     if (this.loading) return;
 
-    const user = this.props.user;
+    const user = this.attrs.user;
     const data = new FormData();
     data.append('avatar', file);
 
@@ -179,9 +171,9 @@ export default class AvatarEditor extends Component {
     app
       .request({
         method: 'POST',
-        url: app.forum.attribute('apiUrl') + '/users/' + user.id() + '/avatar',
+        url: `${app.forum.attribute('apiUrl')}/users/${user.id()}/avatar`,
         serialize: (raw) => raw,
-        data,
+        body: data,
       })
       .then(this.success.bind(this), this.failure.bind(this));
   }
@@ -190,7 +182,7 @@ export default class AvatarEditor extends Component {
    * Remove the user's avatar.
    */
   remove() {
-    const user = this.props.user;
+    const user = this.attrs.user;
 
     this.loading = true;
     m.redraw();
@@ -198,7 +190,7 @@ export default class AvatarEditor extends Component {
     app
       .request({
         method: 'DELETE',
-        url: app.forum.attribute('apiUrl') + '/users/' + user.id() + '/avatar',
+        url: `${app.forum.attribute('apiUrl')}/users/${user.id()}/avatar`,
       })
       .then(this.success.bind(this), this.failure.bind(this));
   }
@@ -212,7 +204,7 @@ export default class AvatarEditor extends Component {
    */
   success(response) {
     app.store.pushPayload(response);
-    delete this.props.user.avatarColor;
+    delete this.attrs.user.avatarColor;
 
     this.loading = false;
     m.redraw();

js/src/forum/components/ChangeEmailModal.js

@@ -6,8 +6,8 @@ import Button from '../../common/components/Button';
  * to change their email address.
  */
 export default class ChangeEmailModal extends Modal {
-  init() {
-    super.init();
+  oninit(vnode) {
+    super.oninit(vnode);
 
     /**
      * Whether or not the email has been changed successfully.
@@ -21,14 +21,14 @@ export default class ChangeEmailModal extends Modal {
      *
      * @type {function}
      */
-    this.email = m.prop(app.session.user.email());
+    this.email = m.stream(app.session.user.email());
 
     /**
      * The value of the password input.
      *
      * @type {function}
      */
-    this.password = m.prop('');
+    this.password = m.stream('');
   }
 
   className() {
@@ -81,12 +81,14 @@ export default class ChangeEmailModal extends Modal {
             />
           </div>
           <div className="Form-group">
-            {Button.component({
+            {Button.component(
+              {
                 className: 'Button Button--primary Button--block',
                 type: 'submit',
                 loading: this.loading,
-              children: app.translator.trans('core.forum.change_email.submit_button'),
-            })}
+              },
+              app.translator.trans('core.forum.change_email.submit_button')
+            )}
           </div>
         </div>
       </div>
@@ -122,7 +124,7 @@ export default class ChangeEmailModal extends Modal {
 
   onerror(error) {
     if (error.status === 401) {
-      error.alert.children = app.translator.trans('core.forum.change_email.incorrect_password_message');
+      error.alert.content = app.translator.trans('core.forum.change_email.incorrect_password_message');
     }
 
     super.onerror(error);

js/src/forum/components/ChangePasswordModal.js

@@ -20,12 +20,14 @@ export default class ChangePasswordModal extends Modal {
         <div className="Form Form--centered">
           <p className="helpText">{app.translator.trans('core.forum.change_password.text')}</p>
           <div className="Form-group">
-            {Button.component({
+            {Button.component(
+              {
                 className: 'Button Button--primary Button--block',
                 type: 'submit',
                 loading: this.loading,
-              children: app.translator.trans('core.forum.change_password.send_button'),
-            })}
+              },
+              app.translator.trans('core.forum.change_password.send_button')
+            )}
           </div>
         </div>
       </div>
@@ -41,7 +43,7 @@ export default class ChangePasswordModal extends Modal {
       .request({
         method: 'POST',
         url: app.forum.attribute('apiUrl') + '/forgot',
-        data: { email: app.session.user.email() },
+        body: { email: app.session.user.email() },
       })
       .then(this.hide.bind(this), this.loaded.bind(this));
   }

js/src/forum/components/CommentPost.js

@@ -1,5 +1,3 @@
-/*global s9e, hljs*/
-
 import Post from './Post';
 import classList from '../../common/utils/classList';
 import PostUser from './PostUser';
@@ -9,19 +7,20 @@ import EditPostComposer from './EditPostComposer';
 import ItemList from '../../common/utils/ItemList';
 import listItems from '../../common/helpers/listItems';
 import Button from '../../common/components/Button';
+import ComposerPostPreview from './ComposerPostPreview';
 
 /**
  * The `CommentPost` component displays a standard `comment`-typed post. This
  * includes a number of item lists (controls, header, and footer) surrounding
  * the post's HTML content.
  *
- * ### Props
+ * ### Attrs
  *
  * - `post`
  */
 export default class CommentPost extends Post {
-  init() {
-    super.init();
+  oninit(vnode) {
+    super.oninit(vnode);
 
     /**
      * If the post has been hidden, then this flag determines whether or not its
@@ -41,48 +40,46 @@ export default class CommentPost extends Post {
 
     this.subtree.check(
       () => this.cardVisible,
-      () => this.isEditing()
+      () => this.isEditing(),
+      () => this.revealContent
     );
   }
 
   content() {
-    // Note: we avoid using JSX for the <ul> below because it results in some
-    // weirdness in Mithril.js 0.1.x (see flarum/core#975). This workaround can
-    // be reverted when we upgrade to Mithril 1.0.
-    return super
-      .content()
-      .concat([
-        <header className="Post-header">{m('ul', listItems(this.headerItems().toArray()))}</header>,
+    return super.content().concat([
+      <header className="Post-header">
+        <ul>{listItems(this.headerItems().toArray())}</ul>
+      </header>,
       <div className="Post-body">
-          {this.isEditing() ? <div className="Post-preview" config={this.configPreview.bind(this)} /> : m.trust(this.props.post.contentHtml())}
+        {this.isEditing() ? <ComposerPostPreview className="Post-preview" composer={app.composer} /> : m.trust(this.attrs.post.contentHtml())}
       </div>,
     ]);
   }
 
-  config(isInitialized, context) {
-    super.config(...arguments);
+  onupdate(vnode) {
+    super.onupdate();
 
-    const contentHtml = this.isEditing() ? '' : this.props.post.contentHtml();
+    const contentHtml = this.isEditing() ? '' : this.attrs.post.contentHtml();
 
     // If the post content has changed since the last render, we'll run through
     // all of the <script> tags in the content and evaluate them. This is
     // necessary because TextFormatter outputs them for e.g. syntax highlighting.
-    if (context.contentHtml !== contentHtml) {
+    if (this.contentHtml !== contentHtml) {
       this.$('.Post-body script').each(function () {
         eval.call(window, $(this).text());
       });
     }
 
-    context.contentHtml = contentHtml;
+    this.contentHtml = contentHtml;
   }
 
   isEditing() {
-    return app.composer.bodyMatches(EditPostComposer, { post: this.props.post });
+    return app.composer.bodyMatches(EditPostComposer, { post: this.attrs.post });
   }
 
-  attrs() {
-    const post = this.props.post;
-    const attrs = super.attrs();
+  elementAttrs() {
+    const post = this.attrs.post;
+    const attrs = super.elementAttrs();
 
     attrs.className =
       (attrs.className || '') +
@@ -98,27 +95,6 @@ export default class CommentPost extends Post {
     return attrs;
   }
 
-  configPreview(element, isInitialized, context) {
-    if (isInitialized) return;
-
-    // Every 50ms, if the composer content has changed, then update the post's
-    // body with a preview.
-    let preview;
-    const updatePreview = () => {
-      const content = app.composer.fields.content();
-
-      if (preview === content) return;
-
-      preview = content;
-
-      s9e.TextFormatter.preview(preview || '', element);
-    };
-    updatePreview();
-
-    const updateInterval = setInterval(updatePreview, 50);
-    context.onunload = () => clearInterval(updateInterval);
-  }
-
   /**
    * Toggle the visibility of a hidden post's content.
    */
@@ -133,7 +109,7 @@ export default class CommentPost extends Post {
    */
   headerItems() {
     const items = new ItemList();
-    const post = this.props.post;
+    const post = this.attrs.post;
 
     items.add(
       'user',

js/src/forum/components/Composer.js

@@ -11,13 +11,15 @@ import ComposerState from '../states/ComposerState';
  * `show`, `hide`, `close`, `minimize`, `fullScreen`, and `exitFullScreen`.
  */
 export default class Composer extends Component {
-  init() {
+  oninit(vnode) {
+    super.oninit(vnode);
+
     /**
      * The composer's "state".
      *
      * @type {ComposerState}
      */
-    this.state = this.props.state;
+    this.state = this.attrs.state;
 
     /**
      * Whether or not the composer currently has focus.
@@ -45,7 +47,7 @@ export default class Composer extends Component {
 
     return (
       <div className={'Composer ' + classList(classes)}>
-        <div className="Composer-handle" config={this.configHandle.bind(this)} />
+        <div className="Composer-handle" oncreate={this.configHandle.bind(this)} />
         <ul className="Composer-controls">{listItems(this.controlItems().toArray())}</ul>
         <div className="Composer-content" onclick={showIfMinimized}>
           {body.componentClass ? body.componentClass.component({ ...body.attrs, composer: this.state, disabled: classes.minimized }) : ''}
@@ -54,7 +56,7 @@ export default class Composer extends Component {
     );
   }
 
-  config(isInitialized, context) {
+  onupdate() {
     if (this.state.position === this.prevPosition) {
       // Set the height of the Composer element and its contents on each redraw,
       // so that they do not lose it if their DOM elements are recreated.
@@ -64,12 +66,10 @@ export default class Composer extends Component {
 
       this.prevPosition = this.state.position;
     }
+  }
 
-    if (isInitialized) return;
-
-    // Since this component is a part of the global UI that persists between
-    // routes, we will flag the DOM to be retained across route changes.
-    context.retain = true;
+  oncreate(vnode) {
+    super.oncreate(vnode);
 
     this.initializeHeight();
     this.$().hide().css('bottom', -this.state.computedHeight());
@@ -84,36 +84,31 @@ export default class Composer extends Component {
     // When the escape key is pressed on any inputs, close the composer.
     this.$().on('keydown', ':input', 'esc', () => this.state.close());
 
-    const handlers = {};
+    this.handlers = {};
 
     $(window)
-      .on('resize', (handlers.onresize = this.updateHeight.bind(this)))
+      .on('resize', (this.handlers.onresize = this.updateHeight.bind(this)))
       .resize();
 
     $(document)
-      .on('mousemove', (handlers.onmousemove = this.onmousemove.bind(this)))
-      .on('mouseup', (handlers.onmouseup = this.onmouseup.bind(this)));
+      .on('mousemove', (this.handlers.onmousemove = this.onmousemove.bind(this)))
+      .on('mouseup', (this.handlers.onmouseup = this.onmouseup.bind(this)));
+  }
 
-    context.onunload = () => {
-      $(window).off('resize', handlers.onresize);
+  onremove() {
+    $(window).off('resize', this.handlers.onresize);
 
-      $(document).off('mousemove', handlers.onmousemove).off('mouseup', handlers.onmouseup);
-    };
+    $(document).off('mousemove', this.handlers.onmousemove).off('mouseup', this.handlers.onmouseup);
   }
 
   /**
    * Add the necessary event handlers to the composer's handle so that it can
    * be used to resize the composer.
-   *
-   * @param {DOMElement} element
-   * @param {Boolean} isInitialized
    */
-  configHandle(element, isInitialized) {
-    if (isInitialized) return;
-
+  configHandle(vnode) {
     const composer = this;
 
-    $(element)
+    $(vnode.dom)
       .css('cursor', 'row-resize')
       .bind('dragstart mousedown', (e) => e.preventDefault())
       .mousedown(function (e) {

js/src/forum/components/ComposerBody.js

@@ -11,7 +11,7 @@ import ItemList from '../../common/utils/ItemList';
  * composer. Subclasses should implement the `onsubmit` method and override
  * `headerTimes`.
  *
- * ### Props
+ * ### Attrs
  *
  * - `composer`
  * - `originalContent`
@@ -24,8 +24,10 @@ import ItemList from '../../common/utils/ItemList';
  * @abstract
  */
 export default class ComposerBody extends Component {
-  init() {
-    this.composer = this.props.composer;
+  oninit(vnode) {
+    super.oninit(vnode);
+
+    this.composer = this.attrs.composer;
 
     /**
      * Whether or not the component is loading.
@@ -37,11 +39,11 @@ export default class ComposerBody extends Component {
     // Let the composer state know to ask for confirmation under certain
     // circumstances, if the body supports / requires it and has a corresponding
     // confirmation question to ask.
-    if (this.props.confirmExit) {
-      this.composer.preventClosingWhen(() => this.hasChanges(), this.props.confirmExit);
+    if (this.attrs.confirmExit) {
+      this.composer.preventClosingWhen(() => this.hasChanges(), this.attrs.confirmExit);
     }
 
-    this.composer.fields.content(this.props.originalContent || '');
+    this.composer.fields.content(this.attrs.originalContent || '');
 
     /**
      * @deprecated BC layer, remove in Beta 15.
@@ -53,15 +55,15 @@ export default class ComposerBody extends Component {
   view() {
     return (
       <ConfirmDocumentUnload when={this.hasChanges.bind(this)}>
-        <div className={'ComposerBody ' + (this.props.className || '')}>
-          {avatar(this.props.user, { className: 'ComposerBody-avatar' })}
+        <div className={'ComposerBody ' + (this.attrs.className || '')}>
+          {avatar(this.attrs.user, { className: 'ComposerBody-avatar' })}
           <div className="ComposerBody-content">
             <ul className="ComposerBody-header">{listItems(this.headerItems().toArray())}</ul>
             <div className="ComposerBody-editor">
               {TextEditor.component({
-                submitLabel: this.props.submitLabel,
-                placeholder: this.props.placeholder,
-                disabled: this.loading || this.props.disabled,
+                submitLabel: this.attrs.submitLabel,
+                placeholder: this.attrs.placeholder,
+                disabled: this.loading || this.attrs.disabled,
                 composer: this.composer,
                 preview: this.jumpToPreview && this.jumpToPreview.bind(this),
                 onchange: this.composer.fields.content,
@@ -84,7 +86,7 @@ export default class ComposerBody extends Component {
   hasChanges() {
     const content = this.composer.fields.content();
 
-    return content && content !== this.props.originalContent;
+    return content && content !== this.attrs.originalContent;
   }
 
   /**

js/src/forum/components/ComposerButton.js

@@ -5,9 +5,9 @@ import Button from '../../common/components/Button';
  * controls.
  */
 export default class ComposerButton extends Button {
-  static initProps(props) {
-    super.initProps(props);
+  static initAttrs(attrs) {
+    super.initAttrs(attrs);
 
-    props.className = props.className || 'Button Button--icon Button--link';
+    attrs.className = attrs.className || 'Button Button--icon Button--link';
   }
 }

js/src/forum/components/ComposerPostPreview.js

@@ -0,0 +1,54 @@
+/*global s9e*/
+
+import Component from '../../common/Component';
+
+/**
+ * The `ComposerPostPreview` component renders Markdown as HTML using the
+ * TextFormatter library, polling a data source for changes every 50ms. This is
+ * done to prevent expensive redraws on e.g. every single keystroke, while
+ * still retaining the perception of live updates for the user.
+ *
+ * ### Attrs
+ *
+ * - `composer` The state of the composer controlling this preview.
+ * - `className` A CSS class for the element surrounding the preview.
+ * - `surround` A callback that can execute code before and after re-render, e.g. for scroll anchoring.
+ */
+export default class ComposerPostPreview extends Component {
+  static initAttrs(attrs) {
+    attrs.className = attrs.className || '';
+    attrs.surround = attrs.surround || ((preview) => preview());
+  }
+
+  view() {
+    return <div className={this.attrs.className} />;
+  }
+
+  oncreate(vnode) {
+    super.oncreate(vnode);
+
+    // Every 50ms, if the composer content has changed, then update the post's
+    // body with a preview.
+    let preview;
+    const updatePreview = () => {
+      // Since we're polling, the composer may have been closed in the meantime,
+      // so we bail in that case.
+      if (!this.attrs.composer.isVisible()) return;
+
+      const content = this.attrs.composer.fields.content();
+
+      if (preview === content) return;
+
+      preview = content;
+
+      this.attrs.surround(() => s9e.TextFormatter.preview(preview || '', vnode.dom));
+    };
+    updatePreview();
+
+    this.updateInterval = setInterval(updatePreview, 50);
+  }
+
+  onremove() {
+    clearInterval(this.updateInterval);
+  }
+}

js/src/forum/components/DiscussionComposer.js

@@ -7,16 +7,26 @@ import extractText from '../../common/utils/extractText';
  * enter the title of their discussion. It also overrides the `submit` and
  * `willExit` actions to account for the title.
  *
- * ### Props
+ * ### Attrs
  *
- * - All of the props for ComposerBody
+ * - All of the attrs for ComposerBody
  * - `titlePlaceholder`
  */
 export default class DiscussionComposer extends ComposerBody {
-  init() {
-    super.init();
+  static initAttrs(attrs) {
+    super.initAttrs(attrs);
 
-    this.composer.fields.title = this.composer.fields.title || m.prop('');
+    attrs.placeholder = attrs.placeholder || extractText(app.translator.trans('core.forum.composer_discussion.body_placeholder'));
+    attrs.submitLabel = attrs.submitLabel || app.translator.trans('core.forum.composer_discussion.submit_button');
+    attrs.confirmExit = attrs.confirmExit || extractText(app.translator.trans('core.forum.composer_discussion.discard_confirmation'));
+    attrs.titlePlaceholder = attrs.titlePlaceholder || extractText(app.translator.trans('core.forum.composer_discussion.title_placeholder'));
+    attrs.className = 'ComposerBody--discussion';
+  }
+
+  oninit(vnode) {
+    super.oninit(vnode);
+
+    this.composer.fields.title = this.composer.fields.title || m.stream('');
 
     /**
      * The value of the title input.
@@ -26,16 +36,6 @@ export default class DiscussionComposer extends ComposerBody {
     this.title = this.composer.fields.title;
   }
 
-  static initProps(props) {
-    super.initProps(props);
-
-    props.placeholder = props.placeholder || extractText(app.translator.trans('core.forum.composer_discussion.body_placeholder'));
-    props.submitLabel = props.submitLabel || app.translator.trans('core.forum.composer_discussion.submit_button');
-    props.confirmExit = props.confirmExit || extractText(app.translator.trans('core.forum.composer_discussion.discard_confirmation'));
-    props.titlePlaceholder = props.titlePlaceholder || extractText(app.translator.trans('core.forum.composer_discussion.title_placeholder'));
-    props.className = 'ComposerBody--discussion';
-  }
-
   headerItems() {
     const items = super.headerItems();
 
@@ -46,10 +46,9 @@ export default class DiscussionComposer extends ComposerBody {
       <h3>
         <input
           className="FormControl"
-          value={this.title()}
-          oninput={m.withAttr('value', this.title)}
-          placeholder={this.props.titlePlaceholder}
-          disabled={!!this.props.disabled}
+          bidi={this.title}
+          placeholder={this.attrs.titlePlaceholder}
+          disabled={!!this.attrs.disabled}
           onkeydown={this.onkeydown.bind(this)}
         />
       </h3>
@@ -71,7 +70,7 @@ export default class DiscussionComposer extends ComposerBody {
       this.composer.editor.moveCursorTo(0);
     }
 
-    m.redraw.strategy('none');
+    e.redraw = false;
   }
 
   hasChanges() {
@@ -101,7 +100,7 @@ export default class DiscussionComposer extends ComposerBody {
       .then((discussion) => {
         this.composer.hide();
         app.discussions.refresh();
-        m.route(app.route.discussion(discussion));
+        m.route.set(app.route.discussion(discussion));
       }, this.loaded.bind(this));
   }
 }

js/src/forum/components/DiscussionHero.js

@@ -5,7 +5,7 @@ import listItems from '../../common/helpers/listItems';
 /**
  * The `DiscussionHero` component displays the hero on a discussion page.
  *
- * ### Props
+ * ### attrs
  *
  * - `discussion`
  */
@@ -27,7 +27,7 @@ export default class DiscussionHero extends Component {
    */
   items() {
     const items = new ItemList();
-    const discussion = this.props.discussion;
+    const discussion = this.attrs.discussion;
     const badges = discussion.badges().toArray();
 
     if (badges.length) {

js/src/forum/components/DiscussionList.js

@@ -7,17 +7,13 @@ import Placeholder from '../../common/components/Placeholder';
 /**
  * The `DiscussionList` component displays a list of discussions.
  *
- * ### Props
+ * ### Attrs
  *
  * - `state` A DiscussionListState object that represents the discussion lists's state.
  */
 export default class DiscussionList extends Component {
-  init() {
-    this.state = this.props.state;
-  }
-
   view() {
-    const state = this.state;
+    const state = this.attrs.state;
 
     const params = state.getParams();
     let loading;
@@ -25,11 +21,13 @@ export default class DiscussionList extends Component {
     if (state.isLoading()) {
       loading = LoadingIndicator.component();
     } else if (state.moreResults) {
-      loading = Button.component({
-        children: app.translator.trans('core.forum.discussion_list.load_more_button'),
+      loading = Button.component(
+        {
           className: 'Button',
           onclick: state.loadMore.bind(state),
-      });
+        },
+        app.translator.trans('core.forum.discussion_list.load_more_button')
+      );
     }
 
     if (state.empty()) {

js/src/forum/components/DiscussionListItem.js

@@ -8,7 +8,6 @@ import ItemList from '../../common/utils/ItemList';
 import abbreviateNumber from '../../common/utils/abbreviateNumber';
 import Dropdown from '../../common/components/Dropdown';
 import TerminalPost from './TerminalPost';
-import PostPreview from './PostPreview';
 import SubtreeRetainer from '../../common/utils/SubtreeRetainer';
 import DiscussionControls from '../utils/DiscussionControls';
 import slidable from '../utils/slidable';
@@ -20,13 +19,15 @@ import { escapeRegExp } from 'lodash-es';
  * The `DiscussionListItem` component shows a single discussion in the
  * discussion list.
  *
- * ### Props
+ * ### Attrs
  *
  * - `discussion`
  * - `params`
  */
 export default class DiscussionListItem extends Component {
-  init() {
+  oninit(vnode) {
+    super.oninit(vnode);
+
     /**
      * Set up a subtree retainer so that the discussion will not be redrawn
      * unless new data comes in.
@@ -34,7 +35,7 @@ export default class DiscussionListItem extends Component {
      * @type {SubtreeRetainer}
      */
     this.subtree = new SubtreeRetainer(
-      () => this.props.discussion.freshness,
+      () => this.attrs.discussion.freshness,
       () => {
         const time = app.session.user && app.session.user.markedAllAsReadAt();
         return time && time.getTime();
@@ -43,37 +44,33 @@ export default class DiscussionListItem extends Component {
     );
   }
 
-  attrs() {
+  elementAttrs() {
     return {
       className: classList([
         'DiscussionListItem',
         this.active() ? 'active' : '',
-        this.props.discussion.isHidden() ? 'DiscussionListItem--hidden' : '',
+        this.attrs.discussion.isHidden() ? 'DiscussionListItem--hidden' : '',
       ]),
     };
   }
 
   view() {
-    const retain = this.subtree.retain();
-
-    if (retain) return retain;
-
-    const discussion = this.props.discussion;
+    const discussion = this.attrs.discussion;
     const user = discussion.user();
     const isUnread = discussion.isUnread();
     const isRead = discussion.isRead();
     const showUnread = !this.showRepliesCount() && isUnread;
     let jumpTo = 0;
     const controls = DiscussionControls.controls(discussion, this).toArray();
-    const attrs = this.attrs();
+    const attrs = this.elementAttrs();
 
-    if (this.props.params.q) {
+    if (this.attrs.params.q) {
       const post = discussion.mostRelevantPost();
       if (post) {
         jumpTo = post.number();
       }
 
-      const phrase = escapeRegExp(this.props.params.q);
+      const phrase = escapeRegExp(this.attrs.params.q);
       this.highlightRegExp = new RegExp(phrase + '|' + phrase.trim().replace(/\s+/g, '|'), 'gi');
     } else {
       jumpTo = Math.min(discussion.lastPostNumber(), (discussion.lastReadPostNumber() || 0) + 1);
@@ -82,12 +79,14 @@ export default class DiscussionListItem extends Component {
     return (
       <div {...attrs}>
         {controls.length
-          ? Dropdown.component({
+          ? Dropdown.component(
+              {
                 icon: 'fas fa-ellipsis-v',
-              children: controls,
                 className: 'DiscussionListItem-controls',
                 buttonClassName: 'Button Button--icon Button--flat Slidable-underneath Slidable-underneath--right',
-            })
+              },
+              controls
+            )
           : ''}
 
         <a
@@ -99,14 +98,13 @@ export default class DiscussionListItem extends Component {
 
         <div className={'DiscussionListItem-content Slidable-content' + (isUnread ? ' unread' : '') + (isRead ? ' read' : '')}>
           <a
-            href={user ? app.route.user(user) : '#'}
+            route={user ? app.route.user(user) : '#'}
             className="DiscussionListItem-author"
             title={extractText(
               app.translator.trans('core.forum.discussion_list.started_text', { user: user, ago: humanTime(discussion.createdAt()) })
             )}
-            config={function (element) {
-              $(element).tooltip({ placement: 'right' });
-              m.route.apply(this, arguments);
+            oncreate={function (vnode) {
+              $(vnode.dom).tooltip({ placement: 'right' });
             }}
           >
             {avatar(user, { title: '' })}
@@ -114,7 +112,7 @@ export default class DiscussionListItem extends Component {
 
           <ul className="DiscussionListItem-badges badges">{listItems(discussion.badges().toArray())}</ul>
 
-          <a href={app.route.discussion(discussion, jumpTo)} config={m.route} className="DiscussionListItem-main">
+          <a route={app.route.discussion(discussion, jumpTo)} className="DiscussionListItem-main">
             <h3 className="DiscussionListItem-title">{highlight(discussion.title(), this.highlightRegExp)}</h3>
             <ul className="DiscussionListItem-info">{listItems(this.infoItems().toArray())}</ul>
           </a>
@@ -131,8 +129,8 @@ export default class DiscussionListItem extends Component {
     );
   }
 
-  config(isInitialized) {
-    if (isInitialized) return;
+  oncreate(vnode) {
+    super.oncreate(vnode);
 
     // If we're on a touch device, set up the discussion row to be slidable.
     // This allows the user to drag the row to either side of the screen to
@@ -144,6 +142,12 @@ export default class DiscussionListItem extends Component {
     }
   }
 
+  onbeforeupdate(vnode, old) {
+    super.onbeforeupdate(vnode, old);
+
+    return this.subtree.needsRebuild();
+  }
+
   /**
    * Determine whether or not the discussion is currently being viewed.
    *
@@ -152,7 +156,7 @@ export default class DiscussionListItem extends Component {
   active() {
     const idParam = m.route.param('id');
 
-    return idParam && idParam.split('-')[0] === this.props.discussion.id();
+    return idParam && idParam.split('-')[0] === this.attrs.discussion.id();
   }
 
   /**
@@ -163,7 +167,7 @@ export default class DiscussionListItem extends Component {
    * @return {Boolean}
    */
   showFirstPost() {
-    return ['newest', 'oldest'].indexOf(this.props.params.sort) !== -1;
+    return ['newest', 'oldest'].indexOf(this.attrs.params.sort) !== -1;
   }
 
   /**
@@ -173,14 +177,14 @@ export default class DiscussionListItem extends Component {
    * @return {Boolean}
    */
   showRepliesCount() {
-    return this.props.params.sort === 'replies';
+    return this.attrs.params.sort === 'replies';
   }
 
   /**
    * Mark the discussion as read.
    */
   markAsRead() {
-    const discussion = this.props.discussion;
+    const discussion = this.attrs.discussion;
 
     if (discussion.isUnread()) {
       discussion.save({ lastReadPostNumber: discussion.lastPostNumber() });
@@ -197,8 +201,8 @@ export default class DiscussionListItem extends Component {
   infoItems() {
     const items = new ItemList();
 
-    if (this.props.params.q) {
-      const post = this.props.discussion.mostRelevantPost() || this.props.discussion.firstPost();
+    if (this.attrs.params.q) {
+      const post = this.attrs.discussion.mostRelevantPost() || this.attrs.discussion.firstPost();
 
       if (post && post.contentType() === 'comment') {
         const excerpt = highlight(post.contentPlain(), this.highlightRegExp, 175);
@@ -208,7 +212,7 @@ export default class DiscussionListItem extends Component {
       items.add(
         'terminalPost',
         TerminalPost.component({
-          discussion: this.props.discussion,
+          discussion: this.attrs.discussion,
           lastPost: !this.showFirstPost(),
         })
       );

js/src/forum/components/DiscussionListPane.js

@@ -0,0 +1,67 @@
+import DiscussionList from './DiscussionList';
+import Component from '../../common/Component';
+
+const hotEdge = (e) => {
+  if (e.pageX < 10) app.pane.show();
+};
+
+/**
+ * The `DiscussionListPane` component displays the list of previously viewed
+ * discussions in a panel that can be displayed by moving the mouse to the left
+ * edge of the screen, where it can also be pinned in place.
+ *
+ * ### Attrs
+ *
+ * - `state` A DiscussionListState object that represents the discussion lists's state.
+ */
+export default class DiscussionListPane extends Component {
+  view() {
+    if (!this.attrs.state.hasDiscussions()) {
+      return;
+    }
+
+    return <div className="DiscussionPage-list">{this.enoughSpace() && <DiscussionList state={this.attrs.state} />}</div>;
+  }
+
+  oncreate(vnode) {
+    super.oncreate(vnode);
+
+    const $list = $(vnode.dom);
+
+    // When the mouse enters and leaves the discussions pane, we want to show
+    // and hide the pane respectively. We also create a 10px 'hot edge' on the
+    // left of the screen to activate the pane.
+    const pane = app.pane;
+    $list.hover(pane.show.bind(pane), pane.onmouseleave.bind(pane));
+
+    $(document).on('mousemove', hotEdge);
+
+    // If the discussion we are viewing is listed in the discussion list, then
+    // we will make sure it is visible in the viewport – if it is not we will
+    // scroll the list down to it.
+    const $discussion = $list.find('.DiscussionListItem.active');
+    if ($discussion.length) {
+      const listTop = $list.offset().top;
+      const listBottom = listTop + $list.outerHeight();
+      const discussionTop = $discussion.offset().top;
+      const discussionBottom = discussionTop + $discussion.outerHeight();
+
+      if (discussionTop < listTop || discussionBottom > listBottom) {
+        $list.scrollTop($list.scrollTop() - listTop + discussionTop);
+      }
+    }
+  }
+
+  onremove() {
+    $(document).off('mousemove', hotEdge);
+  }
+
+  /**
+   * Are we on a device that's larger than we consider "mobile"?
+   *
+   * @returns {boolean}
+   */
+  enoughSpace() {
+    return !$('.App-navigation').is(':visible');
+  }
+}

js/src/forum/components/DiscussionPage.js

@@ -1,13 +1,13 @@
 import Page from '../../common/components/Page';
 import ItemList from '../../common/utils/ItemList';
 import DiscussionHero from './DiscussionHero';
+import DiscussionListPane from './DiscussionListPane';
 import PostStream from './PostStream';
 import PostStreamScrubber from './PostStreamScrubber';
 import LoadingIndicator from '../../common/components/LoadingIndicator';
 import SplitDropdown from '../../common/components/SplitDropdown';
 import listItems from '../../common/helpers/listItems';
 import DiscussionControls from '../utils/DiscussionControls';
-import DiscussionList from './DiscussionList';
 import PostStreamState from '../states/PostStreamState';
 
 /**
@@ -15,8 +15,8 @@ import PostStreamState from '../states/PostStreamState';
  * the discussion list pane, the hero, the posts, and the sidebar.
  */
 export default class DiscussionPage extends Page {
-  init() {
-    super.init();
+  oninit(vnode) {
+    super.oninit(vnode);
 
     /**
      * The discussion that is being viewed.
@@ -42,38 +42,16 @@ export default class DiscussionPage extends Page {
     if (app.discussions.hasDiscussions()) {
       app.pane.enable();
       app.pane.hide();
-
-      if (app.previous.matches(DiscussionPage)) {
-        m.redraw.strategy('diff');
-      }
     }
 
     app.history.push('discussion');
 
     this.bodyClass = 'App--discussion';
+
+    this.prevRoute = m.route.get();
   }
 
-  onunload(e) {
-    // If we have routed to the same discussion as we were viewing previously,
-    // cancel the unloading of this controller and instead prompt the post
-    // stream to jump to the new 'near' param.
-    if (this.discussion) {
-      const idParam = m.route.param('id');
-
-      if (idParam && idParam.split('-')[0] === this.discussion.id()) {
-        e.preventDefault();
-
-        const near = m.route.param('near') || '1';
-
-        if (near !== String(this.near)) {
-          this.stream.goToNumber(near);
-        }
-
-        this.near = null;
-        return;
-      }
-    }
-
+  onremove() {
     // If we are indeed navigating away from this discussion, then disable the
     // discussion list pane. Also, if we're composing a reply to this
     // discussion, minimize the composer – unless it's empty, in which case
@@ -92,14 +70,7 @@ export default class DiscussionPage extends Page {
 
     return (
       <div className="DiscussionPage">
-        {app.discussions.hasDiscussions() ? (
-          <div className="DiscussionPage-list" config={this.configPane.bind(this)}>
-            {!$('.App-navigation').is(':visible') && <DiscussionList state={app.discussions} />}
-          </div>
-        ) : (
-          ''
-        )}
-
+        <DiscussionListPane state={app.discussions} />
         <div className="DiscussionPage-discussion">
           {discussion
             ? [
@@ -124,11 +95,30 @@ export default class DiscussionPage extends Page {
     );
   }
 
-  config(...args) {
-    super.config(...args);
+  onbeforeupdate(vnode) {
+    super.onbeforeupdate(vnode);
 
+    if (m.route.get() !== this.prevRoute) {
+      this.prevRoute = m.route.get();
+
+      // If we have routed to the same discussion as we were viewing previously,
+      // cancel the unloading of this controller and instead prompt the post
+      // stream to jump to the new 'near' param.
       if (this.discussion) {
-      app.setTitle(this.discussion.title());
+        const idParam = m.route.param('id');
+
+        if (idParam && idParam.split('-')[0] === this.discussion.id()) {
+          const near = m.route.param('near') || '1';
+
+          if (near !== String(this.near)) {
+            this.stream.goToNumber(near);
+          }
+
+          this.near = near;
+        } else {
+          this.oninit(vnode);
+        }
+      }
     }
   }
 
@@ -149,7 +139,7 @@ export default class DiscussionPage extends Page {
       app.store.find('discussions', m.route.param('id').split('-')[0], params).then(this.show.bind(this));
     }
 
-    m.lazyRedraw();
+    m.redraw();
   }
 
   /**
@@ -173,6 +163,7 @@ export default class DiscussionPage extends Page {
     this.discussion = discussion;
 
     app.history.push('discussion', discussion.title());
+    app.setTitle(this.discussion.title());
     app.setTitleCount(0);
 
     // When the API responds with a discussion, it will also include a number of
@@ -209,48 +200,6 @@ export default class DiscussionPage extends Page {
     app.current.set('stream', this.stream);
   }
 
-  /**
-   * Configure the discussion list pane.
-   *
-   * @param {DOMElement} element
-   * @param {Boolean} isInitialized
-   * @param {Object} context
-   */
-  configPane(element, isInitialized, context) {
-    if (isInitialized) return;
-
-    context.retain = true;
-
-    const $list = $(element);
-
-    // When the mouse enters and leaves the discussions pane, we want to show
-    // and hide the pane respectively. We also create a 10px 'hot edge' on the
-    // left of the screen to activate the pane.
-    const pane = app.pane;
-    $list.hover(pane.show.bind(pane), pane.onmouseleave.bind(pane));
-
-    const hotEdge = (e) => {
-      if (e.pageX < 10) pane.show();
-    };
-    $(document).on('mousemove', hotEdge);
-    context.onunload = () => $(document).off('mousemove', hotEdge);
-
-    // If the discussion we are viewing is listed in the discussion list, then
-    // we will make sure it is visible in the viewport – if it is not we will
-    // scroll the list down to it.
-    const $discussion = $list.find('.DiscussionListItem.active');
-    if ($discussion.length) {
-      const listTop = $list.offset().top;
-      const listBottom = listTop + $list.outerHeight();
-      const discussionTop = $discussion.offset().top;
-      const discussionBottom = discussionTop + $discussion.outerHeight();
-
-      if (discussionTop < listTop || discussionBottom > listBottom) {
-        $list.scrollTop($list.scrollTop() - listTop + discussionTop);
-      }
-    }
-  }
-
   /**
    * Build an item list for the contents of the sidebar.
    *
@@ -261,12 +210,14 @@ export default class DiscussionPage extends Page {
 
     items.add(
       'controls',
-      SplitDropdown.component({
-        children: DiscussionControls.controls(this.discussion, this).toArray(),
+      SplitDropdown.component(
+        {
           icon: 'fas fa-ellipsis-v',
           className: 'App-primaryControl',
           buttonClassName: 'Button--primary',
-      })
+        },
+        DiscussionControls.controls(this.discussion, this).toArray()
+      )
     );
 
     items.add(
@@ -295,7 +246,8 @@ export default class DiscussionPage extends Page {
     // replace it into the window's history and our own history stack.
     const url = app.route.discussion(discussion, (this.near = startNumber));
 
-    m.route(url, true);
+    this.prevRoute = url;
+    m.route.set(url, null, { replace: true });
     window.history.replaceState(null, document.title, url);
 
     app.history.push('discussion', discussion.title());

js/src/forum/components/DiscussionRenamedNotification.js

@@ -4,9 +4,9 @@ import Notification from './Notification';
  * The `DiscussionRenamedNotification` component displays a notification which
  * indicates that a discussion has had its title changed.
  *
- * ### Props
+ * ### Attrs
  *
- * - All of the props for Notification
+ * - All of the attrs for Notification
  */
 export default class DiscussionRenamedNotification extends Notification {
   icon() {
@@ -14,12 +14,12 @@ export default class DiscussionRenamedNotification extends Notification {
   }
 
   href() {
-    const notification = this.props.notification;
+    const notification = this.attrs.notification;
 
     return app.route.discussion(notification.subject(), notification.content().postNumber);
   }
 
   content() {
-    return app.translator.trans('core.forum.notifications.discussion_renamed_text', { user: this.props.notification.fromUser() });
+    return app.translator.trans('core.forum.notifications.discussion_renamed_text', { user: this.attrs.notification.fromUser() });
   }
 }

js/src/forum/components/DiscussionRenamedPost.js

@@ -5,9 +5,9 @@ import extractText from '../../common/utils/extractText';
  * The `DiscussionRenamedPost` component displays a discussion event post
  * indicating that the discussion has been renamed.
  *
- * ### Props
+ * ### Attrs
  *
- * - All of the props for EventPost
+ * - All of the attrs for EventPost
  */
 export default class DiscussionRenamedPost extends EventPost {
   icon() {
@@ -22,7 +22,7 @@ export default class DiscussionRenamedPost extends EventPost {
   }
 
   descriptionData() {
-    const post = this.props.post;
+    const post = this.attrs.post;
     const oldTitle = post.content()[0];
     const newTitle = post.content()[1];
 

js/src/forum/components/DiscussionsSearchSource.js

@@ -34,18 +34,20 @@ export default class DiscussionsSearchSource {
     return [
       <li className="Dropdown-header">{app.translator.trans('core.forum.search.discussions_heading')}</li>,
       <li>
-        {LinkButton.component({
+        {LinkButton.component(
+          {
             icon: 'fas fa-search',
-          children: app.translator.trans('core.forum.search.all_discussions_button', { query }),
             href: app.route('index', { q: query }),
-        })}
+          },
+          app.translator.trans('core.forum.search.all_discussions_button', { query })
+        )}
       </li>,
       results.map((discussion) => {
         const mostRelevantPost = discussion.mostRelevantPost();
 
         return (
           <li className="DiscussionSearchResult" data-index={'discussions' + discussion.id()}>
-            <a href={app.route.discussion(discussion, mostRelevantPost && mostRelevantPost.number())} config={m.route}>
+            <a route={app.route.discussion(discussion, mostRelevantPost && mostRelevantPost.number())}>
               <div className="DiscussionSearchResult-title">{highlight(discussion.title(), query)}</div>
               {mostRelevantPost ? <div className="DiscussionSearchResult-excerpt">{highlight(mostRelevantPost.contentPlain(), query, 100)}</div> : ''}
             </a>

js/src/forum/components/DiscussionsUserPage.js

@@ -7,8 +7,8 @@ import DiscussionListState from '../states/DiscussionListState';
  * page.
  */
 export default class DiscussionsUserPage extends UserPage {
-  init() {
-    super.init();
+  oninit(vnode) {
+    super.oninit(vnode);
 
     this.loadUser(m.route.param('username'));
   }

js/src/forum/components/EditPostComposer.js

@@ -14,38 +14,32 @@ function minimizeComposerIfFullScreen(e) {
  * post. It sets the initial content to the content of the post that is being
  * edited, and adds a header control to indicate which post is being edited.
  *
- * ### Props
+ * ### Attrs
  *
- * - All of the props for ComposerBody
+ * - All of the attrs for ComposerBody
  * - `post`
  */
 export default class EditPostComposer extends ComposerBody {
-  static initProps(props) {
-    super.initProps(props);
+  static initAttrs(attrs) {
+    super.initAttrs(attrs);
 
-    props.submitLabel = props.submitLabel || app.translator.trans('core.forum.composer_edit.submit_button');
-    props.confirmExit = props.confirmExit || app.translator.trans('core.forum.composer_edit.discard_confirmation');
-    props.originalContent = props.originalContent || props.post.content();
-    props.user = props.user || props.post.user();
+    attrs.submitLabel = attrs.submitLabel || app.translator.trans('core.forum.composer_edit.submit_button');
+    attrs.confirmExit = attrs.confirmExit || app.translator.trans('core.forum.composer_edit.discard_confirmation');
+    attrs.originalContent = attrs.originalContent || attrs.post.content();
+    attrs.user = attrs.user || attrs.post.user();
 
-    props.post.editedContent = props.originalContent;
+    attrs.post.editedContent = attrs.originalContent;
   }
 
   headerItems() {
     const items = super.headerItems();
-    const post = this.props.post;
-
-    const routeAndMinimize = function (element, isInitialized) {
-      if (isInitialized) return;
-      $(element).on('click', minimizeComposerIfFullScreen);
-      m.route.apply(this, arguments);
-    };
+    const post = this.attrs.post;
 
     items.add(
       'title',
       <h3>
         {icon('fas fa-pencil-alt')}{' '}
-        <a href={app.route.discussion(post.discussion(), post.number())} config={routeAndMinimize}>
+        <a route={app.route.discussion(post.discussion(), post.number())} onclick={minimizeComposerIfFullScreen}>
           {app.translator.trans('core.forum.composer_edit.post_link', { number: post.number(), discussion: post.discussion().title() })}
         </a>
       </h3>
@@ -60,7 +54,7 @@ export default class EditPostComposer extends ComposerBody {
   jumpToPreview(e) {
     minimizeComposerIfFullScreen(e);
 
-    m.route(app.route.post(this.props.post));
+    m.route.set(app.route.post(this.attrs.post));
   }
 
   /**
@@ -75,13 +69,13 @@ export default class EditPostComposer extends ComposerBody {
   }
 
   onsubmit() {
-    const discussion = this.props.post.discussion();
+    const discussion = this.attrs.post.discussion();
 
     this.loading = true;
 
     const data = this.data();
 
-    this.props.post.save(data).then((post) => {
+    this.attrs.post.save(data).then((post) => {
       // If we're currently viewing the discussion which this edit was made
       // in, then we can scroll to the post.
       if (app.viewingDiscussion(discussion)) {
@@ -91,19 +85,23 @@ export default class EditPostComposer extends ComposerBody {
         // their edit has been made, containing a button which will
         // transition to their edited post when clicked.
         let alert;
-        const viewButton = Button.component({
+        const viewButton = Button.component(
+          {
             className: 'Button Button--link',
-          children: app.translator.trans('core.forum.composer_edit.view_button'),
             onclick: () => {
-            m.route(app.route.post(post));
+              m.route.set(app.route.post(post));
               app.alerts.dismiss(alert);
             },
-        });
-        alert = app.alerts.show({
+          },
+          app.translator.trans('core.forum.composer_edit.view_button')
+        );
+        alert = app.alerts.show(
+          {
             type: 'success',
-          children: app.translator.trans('core.forum.composer_edit.edited_message'),
             controls: [viewButton],
-        });
+          },
+          app.translator.trans('core.forum.composer_edit.edited_message')
+        );
       }
 
       this.composer.hide();

js/src/forum/components/EditUserModal.js

@@ -9,22 +9,22 @@ import ItemList from '../../common/utils/ItemList';
  * The `EditUserModal` component displays a modal dialog with a login form.
  */
 export default class EditUserModal extends Modal {
-  init() {
-    super.init();
+  oninit(vnode) {
+    super.oninit(vnode);
 
-    const user = this.props.user;
+    const user = this.attrs.user;
 
-    this.username = m.prop(user.username() || '');
-    this.email = m.prop(user.email() || '');
-    this.isEmailConfirmed = m.prop(user.isEmailConfirmed() || false);
-    this.setPassword = m.prop(false);
-    this.password = m.prop(user.password() || '');
+    this.username = m.stream(user.username() || '');
+    this.email = m.stream(user.email() || '');
+    this.isEmailConfirmed = m.stream(user.isEmailConfirmed() || false);
+    this.setPassword = m.stream(false);
+    this.password = m.stream(user.password() || '');
     this.groups = {};
 
     app.store
       .all('groups')
       .filter((group) => [Group.GUEST_ID, Group.MEMBER_ID].indexOf(group.id()) === -1)
-      .forEach((group) => (this.groups[group.id()] = m.prop(user.groups().indexOf(group) !== -1)));
+      .forEach((group) => (this.groups[group.id()] = m.stream(user.groups().indexOf(group) !== -1)));
   }
 
   className() {
@@ -55,7 +55,7 @@ export default class EditUserModal extends Modal {
       40
     );
 
-    if (app.session.user !== this.props.user) {
+    if (app.session.user !== this.attrs.user) {
       items.add(
         'email',
         <div className="Form-group">
@@ -65,12 +65,14 @@ export default class EditUserModal extends Modal {
           </div>
           {!this.isEmailConfirmed() ? (
             <div>
-              {Button.component({
+              {Button.component(
+                {
                   className: 'Button Button--block',
-                children: app.translator.trans('core.forum.edit_user.activate_button'),
                   loading: this.loading,
                   onclick: this.activate.bind(this),
-              })}
+                },
+                app.translator.trans('core.forum.edit_user.activate_button')
+              )}
             </div>
           ) : (
             ''
@@ -89,9 +91,9 @@ export default class EditUserModal extends Modal {
                 type="checkbox"
                 onchange={(e) => {
                   this.setPassword(e.target.checked);
-                  m.redraw(true);
+                  m.redraw.sync();
                   if (e.target.checked) this.$('[name=password]').select();
-                  m.redraw.strategy('none');
+                  e.redraw = false;
                 }}
               />
               {app.translator.trans('core.forum.edit_user.set_password_label')}
@@ -125,7 +127,7 @@ export default class EditUserModal extends Modal {
                 <input
                   type="checkbox"
                   bidi={this.groups[group.id()]}
-                  disabled={this.props.user.id() === '1' && group.id() === Group.ADMINISTRATOR_ID}
+                  disabled={this.attrs.user.id() === '1' && group.id() === Group.ADMINISTRATOR_ID}
                 />
                 {GroupBadge.component({ group, label: '' })} {group.nameSingular()}
               </label>
@@ -138,12 +140,14 @@ export default class EditUserModal extends Modal {
     items.add(
       'submit',
       <div className="Form-group">
-        {Button.component({
+        {Button.component(
+          {
             className: 'Button Button--primary',
             type: 'submit',
             loading: this.loading,
-          children: app.translator.trans('core.forum.edit_user.submit_button'),
-        })}
+          },
+          app.translator.trans('core.forum.edit_user.submit_button')
+        )}
       </div>,
       -10
     );
@@ -157,7 +161,7 @@ export default class EditUserModal extends Modal {
       username: this.username(),
       isEmailConfirmed: true,
     };
-    this.props.user
+    this.attrs.user
       .save(data, { errorHandler: this.onerror.bind(this) })
       .then(() => {
         this.isEmailConfirmed(true);
@@ -180,7 +184,7 @@ export default class EditUserModal extends Modal {
       relationships: { groups },
     };
 
-    if (app.session.user !== this.props.user) {
+    if (app.session.user !== this.attrs.user) {
       data.email = this.email();
     }
 
@@ -196,7 +200,7 @@ export default class EditUserModal extends Modal {
 
     this.loading = true;
 
-    this.props.user
+    this.attrs.user
       .save(this.data(), { errorHandler: this.onerror.bind(this) })
       .then(this.hide.bind(this))
       .catch(() => {

js/src/forum/components/EventPost.js

@@ -8,28 +8,28 @@ import icon from '../../common/helpers/icon';
  * event, like a discussion being renamed or stickied. Subclasses must implement
  * the `icon` and `description` methods.
  *
- * ### Props
+ * ### Attrs
  *
- * - All of the props for `Post`
+ * - All of the attrs for `Post`
  *
  * @abstract
  */
 export default class EventPost extends Post {
-  attrs() {
-    const attrs = super.attrs();
+  elementAttrs() {
+    const attrs = super.elementAttrs();
 
-    attrs.className = (attrs.className || '') + ' EventPost ' + ucfirst(this.props.post.contentType()) + 'Post';
+    attrs.className = (attrs.className || '') + ' EventPost ' + ucfirst(this.attrs.post.contentType()) + 'Post';
 
     return attrs;
   }
 
   content() {
-    const user = this.props.post.user();
+    const user = this.attrs.post.user();
     const username = usernameHelper(user);
     const data = Object.assign(this.descriptionData(), {
       user,
       username: user ? (
-        <a className="EventPost-user" href={app.route.user(user)} config={m.route}>
+        <a className="EventPost-user" route={app.route.user(user)}>
           {username}
         </a>
       ) : (

js/src/forum/components/ForgotPasswordModal.js

@@ -1,5 +1,4 @@
 import Modal from '../../common/components/Modal';
-import Alert from '../../common/components/Alert';
 import Button from '../../common/components/Button';
 import extractText from '../../common/utils/extractText';
 
@@ -7,20 +6,20 @@ import extractText from '../../common/utils/extractText';
  * The `ForgotPasswordModal` component displays a modal which allows the user to
  * enter their email address and request a link to reset their password.
  *
- * ### Props
+ * ### Attrs
  *
  * - `email`
  */
 export default class ForgotPasswordModal extends Modal {
-  init() {
-    super.init();
+  oninit(vnode) {
+    super.oninit(vnode);
 
     /**
      * The value of the email input.
      *
      * @type {Function}
      */
-    this.email = m.prop(this.props.email || '');
+    this.email = m.stream(this.attrs.email || '');
 
     /**
      * Whether or not the password reset email was sent successfully.
@@ -64,18 +63,19 @@ export default class ForgotPasswordModal extends Modal {
               name="email"
               type="email"
               placeholder={extractText(app.translator.trans('core.forum.forgot_password.email_placeholder'))}
-              value={this.email()}
-              onchange={m.withAttr('value', this.email)}
+              bidi={this.email}
               disabled={this.loading}
             />
           </div>
           <div className="Form-group">
-            {Button.component({
+            {Button.component(
+              {
                 className: 'Button Button--primary Button--block',
                 type: 'submit',
                 loading: this.loading,
-              children: app.translator.trans('core.forum.forgot_password.submit_button'),
-            })}
+              },
+              app.translator.trans('core.forum.forgot_password.submit_button')
+            )}
           </div>
         </div>
       </div>
@@ -91,7 +91,7 @@ export default class ForgotPasswordModal extends Modal {
       .request({
         method: 'POST',
         url: app.forum.attribute('apiUrl') + '/forgot',
-        data: { email: this.email() },
+        body: { email: this.email() },
         errorHandler: this.onerror.bind(this),
       })
       .then(() => {
@@ -104,7 +104,7 @@ export default class ForgotPasswordModal extends Modal {
 
   onerror(error) {
     if (error.status === 404) {
-      error.alert.children = app.translator.trans('core.forum.forgot_password.not_found_message');
+      error.alert.content = app.translator.trans('core.forum.forgot_password.not_found_message');
     }
 
     super.onerror(error);

js/src/forum/components/HeaderPrimary.js

@@ -11,13 +11,6 @@ export default class HeaderPrimary extends Component {
     return <ul className="Header-controls">{listItems(this.items().toArray())}</ul>;
   }
 
-  config(isInitialized, context) {
-    // Since this component is 'above' the content of the page (that is, it is a
-    // part of the global UI that persists between routes), we will flag the DOM
-    // to be retained across route changes.
-    context.retain = true;
-  }
-
   /**
    * Build an item list for the controls.
    *

js/src/forum/components/HeaderSecondary.js

@@ -19,13 +19,6 @@ export default class HeaderSecondary extends Component {
     return <ul className="Header-controls">{listItems(this.items().toArray())}</ul>;
   }
 
-  config(isInitialized, context) {
-    // Since this component is 'above' the content of the page (that is, it is a
-    // part of the global UI that persists between routes), we will flag the DOM
-    // to be retained across route changes.
-    context.retain = true;
-  }
-
   /**
    * Build an item list for the controls.
    *
@@ -41,9 +34,9 @@ export default class HeaderSecondary extends Component {
 
       for (const locale in app.data.locales) {
         locales.push(
-          Button.component({
+          Button.component(
+            {
               active: app.data.locale === locale,
-            children: app.data.locales[locale],
               icon: app.data.locale === locale ? 'fas fa-check' : true,
               onclick: () => {
                 if (app.session.user) {
@@ -53,16 +46,20 @@ export default class HeaderSecondary extends Component {
                   window.location.reload();
                 }
               },
-          })
+            },
+            app.data.locales[locale]
+          )
         );
       }
 
       items.add(
         'locale',
-        SelectDropdown.component({
-          children: locales,
+        SelectDropdown.component(
+          {
             buttonClassName: 'Button Button--link',
-        }),
+          },
+          locales
+        ),
         20
       );
     }
@@ -74,22 +71,26 @@ export default class HeaderSecondary extends Component {
       if (app.forum.attribute('allowSignUp')) {
         items.add(
           'signUp',
-          Button.component({
-            children: app.translator.trans('core.forum.header.sign_up_link'),
+          Button.component(
+            {
               className: 'Button Button--link',
               onclick: () => app.modal.show(SignUpModal),
-          }),
+            },
+            app.translator.trans('core.forum.header.sign_up_link')
+          ),
           10
         );
       }
 
       items.add(
         'logIn',
-        Button.component({
-          children: app.translator.trans('core.forum.header.log_in_link'),
+        Button.component(
+          {
             className: 'Button Button--link',
             onclick: () => app.modal.show(LogInModal),
-        }),
+          },
+          app.translator.trans('core.forum.header.log_in_link')
+        ),
         0
       );
     }

js/src/forum/components/IndexPage.js

@@ -19,8 +19,8 @@ import SelectDropdown from '../../common/components/SelectDropdown';
 export default class IndexPage extends Page {
   static providesInitialSearch = true;
 
-  init() {
-    super.init();
+  oninit(vnode) {
+    super.oninit(vnode);
 
     // If the user is returning from a discussion page, then take note of which
     // discussion they have just visited. After the view is rendered, we will
@@ -42,12 +42,26 @@ export default class IndexPage extends Page {
     app.history.push('index', app.translator.trans('core.forum.header.back_to_index_tooltip'));
 
     this.bodyClass = 'App--index';
+
+    this.currentPath = m.route.get();
   }
 
-  onunload() {
-    // Save the scroll position so we can restore it when we return to the
-    // discussion list.
-    app.cache.scrollTop = $(window).scrollTop();
+  onbeforeupdate(vnode) {
+    super.onbeforeupdate(vnode);
+
+    const curPath = m.route.get();
+
+    if (this.currentPath !== curPath) {
+      this.onNewRoute();
+
+      app.discussions.clear();
+
+      app.discussions.refreshParams(app.search.params());
+
+      this.currentPath = curPath;
+
+      this.setTitle();
+    }
   }
 
   view() {
@@ -72,15 +86,15 @@ export default class IndexPage extends Page {
     );
   }
 
-  config(isInitialized, context) {
-    super.config(...arguments);
-
-    if (isInitialized) return;
-
-    extend(context, 'onunload', () => $('#app').css('min-height', ''));
-
+  setTitle() {
     app.setTitle(app.translator.trans('core.forum.index.meta_title_text'));
     app.setTitleCount(0);
+  }
+
+  oncreate(vnode) {
+    super.oncreate(vnode);
+
+    this.setTitle();
 
     // Work out the difference between the height of this hero and that of the
     // previous hero. Maintain the same scroll position relative to the bottom
@@ -117,6 +131,16 @@ export default class IndexPage extends Page {
     }
   }
 
+  onremove() {
+    super.onremove();
+
+    $('#app').css('min-height', '');
+
+    // Save the scroll position so we can restore it when we return to the
+    // discussion list.
+    app.cache.scrollTop = $(window).scrollTop();
+  }
+
   /**
    * Get the component to display as the hero.
    *
@@ -139,25 +163,31 @@ export default class IndexPage extends Page {
 
     items.add(
       'newDiscussion',
-      Button.component({
-        children: app.translator.trans(
-          canStartDiscussion ? 'core.forum.index.start_discussion_button' : 'core.forum.index.cannot_start_discussion_button'
-        ),
+      Button.component(
+        {
           icon: 'fas fa-edit',
           className: 'Button Button--primary IndexPage-newDiscussion',
           itemClassName: 'App-primaryControl',
-        onclick: this.newDiscussionAction.bind(this),
+          onclick: () => {
+            // If the user is not logged in, the promise rejects, and a login modal shows up.
+            // Since that's already handled, we dont need to show an error message in the console.
+            return this.newDiscussionAction().catch(() => {});
+          },
           disabled: !canStartDiscussion,
-      })
+        },
+        app.translator.trans(canStartDiscussion ? 'core.forum.index.start_discussion_button' : 'core.forum.index.cannot_start_discussion_button')
+      )
     );
 
     items.add(
       'nav',
-      SelectDropdown.component({
-        children: this.navItems(this).toArray(),
+      SelectDropdown.component(
+        {
           buttonClassName: 'Button',
           className: 'App-titleControl',
-      })
+        },
+        this.navItems(this).toArray()
+      )
     );
 
     return items;
@@ -175,11 +205,13 @@ export default class IndexPage extends Page {
 
     items.add(
       'allDiscussions',
-      LinkButton.component({
+      LinkButton.component(
+        {
           href: app.route('index', params),
-        children: app.translator.trans('core.forum.index.all_discussions_link'),
           icon: 'far fa-comments',
-      }),
+        },
+        app.translator.trans('core.forum.index.all_discussions_link')
+      ),
       100
     );
 
@@ -204,21 +236,25 @@ export default class IndexPage extends Page {
 
     items.add(
       'sort',
-      Dropdown.component({
+      Dropdown.component(
+        {
           buttonClassName: 'Button',
           label: sortOptions[app.search.params().sort] || Object.keys(sortMap).map((key) => sortOptions[key])[0],
-        children: Object.keys(sortOptions).map((value) => {
+        },
+        Object.keys(sortOptions).map((value) => {
           const label = sortOptions[value];
           const active = (app.search.params().sort || Object.keys(sortMap)[0]) === value;
 
-          return Button.component({
-            children: label,
+          return Button.component(
+            {
               icon: active ? 'fas fa-check' : true,
               onclick: app.search.changeSort.bind(app.search, value),
               active: active,
-          });
-        }),
+            },
+            label
+          );
         })
+      )
     );
 
     return items;
@@ -270,20 +306,18 @@ export default class IndexPage extends Page {
    * @return {Promise}
    */
   newDiscussionAction() {
-    const deferred = m.deferred();
-
+    return new Promise((resolve, reject) => {
       if (app.session.user) {
         app.composer.load(DiscussionComposer, { user: app.session.user });
         app.composer.show();
 
-      deferred.resolve(app.composer);
+        return resolve(app.composer);
       } else {
-      deferred.reject();
-
         app.modal.show(LogInModal);
-    }
 
-    return deferred.promise;
+        return reject();
+      }
+    });
   }
 
   /**

js/src/forum/components/LogInButton.js

@@ -4,21 +4,21 @@ import Button from '../../common/components/Button';
  * The `LogInButton` component displays a social login button which will open
  * a popup window containing the specified path.
  *
- * ### Props
+ * ### Attrs
  *
  * - `path`
  */
 export default class LogInButton extends Button {
-  static initProps(props) {
-    props.className = (props.className || '') + ' LogInButton';
+  static initAttrs(attrs) {
+    attrs.className = (attrs.className || '') + ' LogInButton';
 
-    props.onclick = function () {
+    attrs.onclick = function () {
       const width = 580;
       const height = 400;
       const $window = $(window);
 
       window.open(
-        app.forum.attribute('baseUrl') + props.path,
+        app.forum.attribute('baseUrl') + attrs.path,
         'logInPopup',
         `width=${width},` +
           `height=${height},` +
@@ -28,6 +28,6 @@ export default class LogInButton extends Button {
       );
     };
 
-    super.initProps(props);
+    super.initAttrs(attrs);
   }
 }

js/src/forum/components/LogInModal.js

@@ -9,35 +9,35 @@ import ItemList from '../../common/utils/ItemList';
 /**
  * The `LogInModal` component displays a modal dialog with a login form.
  *
- * ### Props
+ * ### Attrs
  *
  * - `identification`
  * - `password`
  */
 export default class LogInModal extends Modal {
-  init() {
-    super.init();
+  oninit(vnode) {
+    super.oninit(vnode);
 
     /**
      * The value of the identification input.
      *
      * @type {Function}
      */
-    this.identification = m.prop(this.props.identification || '');
+    this.identification = m.stream(this.attrs.identification || '');
 
     /**
      * The value of the password input.
      *
      * @type {Function}
      */
-    this.password = m.prop(this.props.password || '');
+    this.password = m.stream(this.attrs.password || '');
 
     /**
      * The value of the remember me input.
      *
      * @type {Function}
      */
-    this.remember = m.prop(!!this.props.remember);
+    this.remember = m.stream(!!this.attrs.remember);
   }
 
   className() {
@@ -105,12 +105,14 @@ export default class LogInModal extends Modal {
     items.add(
       'submit',
       <div className="Form-group">
-        {Button.component({
+        {Button.component(
+          {
             className: 'Button Button--primary Button--block',
             type: 'submit',
             loading: this.loading,
-          children: app.translator.trans('core.forum.log_in.submit_button'),
-        })}
+          },
+          app.translator.trans('core.forum.log_in.submit_button')
+        )}
       </div>,
       -10
     );
@@ -140,9 +142,9 @@ export default class LogInModal extends Modal {
    */
   forgotPassword() {
     const email = this.identification();
-    const props = email.indexOf('@') !== -1 ? { email } : undefined;
+    const attrs = email.indexOf('@') !== -1 ? { email } : undefined;
 
-    app.modal.show(ForgotPasswordModal, props);
+    app.modal.show(ForgotPasswordModal, attrs);
   }
 
   /**
@@ -152,11 +154,11 @@ export default class LogInModal extends Modal {
    * @public
    */
   signUp() {
-    const props = { password: this.password() };
+    const attrs = { password: this.password() };
     const identification = this.identification();
-    props[identification.indexOf('@') !== -1 ? 'email' : 'username'] = identification;
+    attrs[identification.indexOf('@') !== -1 ? 'email' : 'username'] = identification;
 
-    app.modal.show(SignUpModal, props);
+    app.modal.show(SignUpModal, attrs);
   }
 
   onready() {
@@ -179,7 +181,7 @@ export default class LogInModal extends Modal {
 
   onerror(error) {
     if (error.status === 401) {
-      error.alert.children = app.translator.trans('core.forum.log_in.invalid_login_message');
+      error.alert.content = app.translator.trans('core.forum.log_in.invalid_login_message');
     }
 
     super.onerror(error);

js/src/forum/components/Notification.js

@@ -8,7 +8,7 @@ import Button from '../../common/components/Button';
  * The `Notification` component abstract displays a single notification.
  * Subclasses should implement the `icon`, `href`, and `content` methods.
  *
- * ### Props
+ * ### Attrs
  *
  * - `notification`
  *
@@ -16,18 +16,17 @@ import Button from '../../common/components/Button';
  */
 export default class Notification extends Component {
   view() {
-    const notification = this.props.notification;
+    const notification = this.attrs.notification;
     const href = this.href();
 
+    const linkAttrs = {};
+    linkAttrs[href.indexOf('://') === -1 ? 'route' : 'href'] = href;
+
     return (
       <a
         className={'Notification Notification--' + notification.contentType() + ' ' + (!notification.isRead() ? 'unread' : '')}
-        href={href}
-        config={function (element, isInitialized) {
-          if (href.indexOf('://') === -1) m.route.apply(this, arguments);
-
-          if (!isInitialized) $(element).click(this.markAsRead.bind(this));
-        }}
+        {...linkAttrs}
+        onclick={this.markAsRead.bind(this)}
       >
         {!notification.isRead() &&
           Button.component({
@@ -86,10 +85,10 @@ export default class Notification extends Component {
    * Mark the notification as read.
    */
   markAsRead() {
-    if (this.props.notification.isRead()) return;
+    if (this.attrs.notification.isRead()) return;
 
     app.session.user.pushAttributes({ unreadNotificationCount: app.session.user.unreadNotificationCount() - 1 });
 
-    this.props.notification.save({ isRead: true });
+    this.attrs.notification.save({ isRead: true });
   }
 }

js/src/forum/components/NotificationGrid.js

@@ -7,12 +7,14 @@ import ItemList from '../../common/utils/ItemList';
  * The `NotificationGrid` component displays a table of notification types and
  * methods, allowing the user to toggle each combination.
  *
- * ### Props
+ * ### Attrs
  *
  * - `user`
  */
 export default class NotificationGrid extends Component {
-  init() {
+  oninit(vnode) {
+    super.oninit(vnode);
+
     /**
      * Information about the available notification methods.
      *
@@ -36,7 +38,7 @@ export default class NotificationGrid extends Component {
   }
 
   view() {
-    const preferences = this.props.user.preferences();
+    const preferences = this.attrs.user.preferences();
 
     return (
       <table className="NotificationGrid">
@@ -62,12 +64,12 @@ export default class NotificationGrid extends Component {
 
                 return (
                   <td className="NotificationGrid-checkbox">
-                    {Checkbox.component({
-                      state: !!preferences[key],
-                      loading: this.loading[key],
-                      disabled: !(key in preferences),
-                      onchange: () => this.toggle([key]),
-                    })}
+                    <Checkbox
+                      state={!!preferences[key]}
+                      loading={this.loading[key]}
+                      disabled={!(key in preferences)}
+                      onchange={this.toggle.bind(this, [key])}
+                    />
                   </td>
                 );
               })}
@@ -78,8 +80,8 @@ export default class NotificationGrid extends Component {
     );
   }
 
-  config(isInitialized) {
-    if (isInitialized) return;
+  oncreate(vnode) {
+    super.oncreate(vnode);
 
     this.$('thead .NotificationGrid-groupToggle').bind('mouseenter mouseleave', function (e) {
       const i = parseInt($(this).index(), 10) + 1;
@@ -104,7 +106,7 @@ export default class NotificationGrid extends Component {
    * @param {Array} keys
    */
   toggle(keys) {
-    const user = this.props.user;
+    const user = this.attrs.user;
     const preferences = user.preferences();
     const enabled = !preferences[keys[0]];
 
@@ -128,7 +130,7 @@ export default class NotificationGrid extends Component {
    * @param {String} method
    */
   toggleMethod(method) {
-    const keys = this.types.map((type) => this.preferenceKey(type.name, method)).filter((key) => key in this.props.user.preferences());
+    const keys = this.types.map((type) => this.preferenceKey(type.name, method)).filter((key) => key in this.attrs.user.preferences());
 
     this.toggle(keys);
   }
@@ -139,7 +141,7 @@ export default class NotificationGrid extends Component {
    * @param {String} type
    */
   toggleType(type) {
-    const keys = this.methods.map((method) => this.preferenceKey(type, method.name)).filter((key) => key in this.props.user.preferences());
+    const keys = this.methods.map((method) => this.preferenceKey(type, method.name)).filter((key) => key in this.attrs.user.preferences());
 
     this.toggle(keys);
   }

js/src/forum/components/NotificationList.js

@@ -9,12 +9,9 @@ import Discussion from '../../common/models/Discussion';
  * notifications, grouped by discussion.
  */
 export default class NotificationList extends Component {
-  init() {
-    this.state = this.props.state;
-  }
-
   view() {
-    const pages = this.state.getNotificationPages();
+    const state = this.attrs.state;
+    const pages = state.getNotificationPages();
 
     return (
       <div className="NotificationList">
@@ -24,7 +21,7 @@ export default class NotificationList extends Component {
               className: 'Button Button--icon Button--link',
               icon: 'fas fa-check',
               title: app.translator.trans('core.forum.notifications.mark_all_as_read_tooltip'),
-              onclick: this.state.markAllAsRead.bind(this.state),
+              onclick: state.markAllAsRead.bind(state),
             })}
           </div>
 
@@ -66,7 +63,7 @@ export default class NotificationList extends Component {
                   return (
                     <div className="NotificationGroup">
                       {group.discussion ? (
-                        <a className="NotificationGroup-header" href={app.route.discussion(group.discussion)} config={m.route}>
+                        <a className="NotificationGroup-header" route={app.route.discussion(group.discussion)}>
                           {badges && badges.length ? <ul className="NotificationGroup-badges badges">{listItems(badges)}</ul> : ''}
                           {group.discussion.title()}
                         </a>
@@ -85,7 +82,7 @@ export default class NotificationList extends Component {
                 });
               })
             : ''}
-          {this.state.isLoading() ? (
+          {state.isLoading() ? (
             <LoadingIndicator className="LoadingIndicator--block" />
           ) : pages.length ? (
             ''
@@ -97,27 +94,31 @@ export default class NotificationList extends Component {
     );
   }
 
-  config(isInitialized, context) {
-    if (isInitialized) return;
+  oncreate(vnode) {
+    super.oncreate(vnode);
 
-    const $notifications = this.$('.NotificationList-content');
-    const $scrollParent = $notifications.css('overflow') === 'auto' ? $notifications : $(window);
+    this.$notifications = this.$('.NotificationList-content');
+    this.$scrollParent = this.$notifications.css('overflow') === 'auto' ? this.$notifications : $(window);
 
-    const scrollHandler = () => {
-      const scrollTop = $scrollParent.scrollTop();
-      const viewportHeight = $scrollParent.height();
-      const contentTop = $scrollParent === $notifications ? 0 : $notifications.offset().top;
-      const contentHeight = $notifications[0].scrollHeight;
-
-      if (this.state.hasMoreResults() && !this.state.isLoading() && scrollTop + viewportHeight >= contentTop + contentHeight) {
-        this.state.loadMore();
+    this.boundScrollHandler = this.scrollHandler.bind(this);
+    this.$scrollParent.on('scroll', this.boundScrollHandler);
   }
-    };
 
-    $scrollParent.on('scroll', scrollHandler);
+  onremove() {
+    this.$scrollParent.off('scroll', this.boundScrollHandler);
+  }
 
-    context.onunload = () => {
-      $scrollParent.off('scroll', scrollHandler);
-    };
+  scrollHandler() {
+    const state = this.attrs.state;
+
+    const scrollTop = this.$scrollParent.scrollTop();
+    const viewportHeight = this.$scrollParent.height();
+
+    const contentTop = this.$scrollParent === this.$notifications ? 0 : this.$notifications.offset().top;
+    const contentHeight = this.$notifications[0].scrollHeight;
+
+    if (state.hasMoreResults() && !state.isLoading() && scrollTop + viewportHeight >= contentTop + contentHeight) {
+      state.loadMore();
+    }
   }
 }

js/src/forum/components/NotificationsDropdown.js

@@ -3,21 +3,21 @@ import icon from '../../common/helpers/icon';
 import NotificationList from './NotificationList';
 
 export default class NotificationsDropdown extends Dropdown {
-  static initProps(props) {
-    props.className = props.className || 'NotificationsDropdown';
-    props.buttonClassName = props.buttonClassName || 'Button Button--flat';
-    props.menuClassName = props.menuClassName || 'Dropdown-menu--right';
-    props.label = props.label || app.translator.trans('core.forum.notifications.tooltip');
-    props.icon = props.icon || 'fas fa-bell';
+  static initAttrs(attrs) {
+    attrs.className = attrs.className || 'NotificationsDropdown';
+    attrs.buttonClassName = attrs.buttonClassName || 'Button Button--flat';
+    attrs.menuClassName = attrs.menuClassName || 'Dropdown-menu--right';
+    attrs.label = attrs.label || app.translator.trans('core.forum.notifications.tooltip');
+    attrs.icon = attrs.icon || 'fas fa-bell';
 
-    super.initProps(props);
+    super.initAttrs(attrs);
   }
 
   getButton() {
     const newNotifications = this.getNewCount();
     const vdom = super.getButton();
 
-    vdom.attrs.title = this.props.label;
+    vdom.attrs.title = this.attrs.label;
 
     vdom.attrs.className += newNotifications ? ' new' : '';
     vdom.attrs.onclick = this.onclick.bind(this);
@@ -29,16 +29,16 @@ export default class NotificationsDropdown extends Dropdown {
     const unread = this.getUnreadCount();
 
     return [
-      icon(this.props.icon, { className: 'Button-icon' }),
+      icon(this.attrs.icon, { className: 'Button-icon' }),
       unread ? <span className="NotificationsDropdown-unread">{unread}</span> : '',
-      <span className="Button-label">{this.props.label}</span>,
+      <span className="Button-label">{this.attrs.label}</span>,
     ];
   }
 
   getMenu() {
     return (
-      <div className={'Dropdown-menu ' + this.props.menuClassName} onclick={this.menuClick.bind(this)}>
-        {this.showing ? NotificationList.component({ state: this.props.state }) : ''}
+      <div className={'Dropdown-menu ' + this.attrs.menuClassName} onclick={this.menuClick.bind(this)}>
+        {this.showing ? NotificationList.component({ state: this.attrs.state }) : ''}
       </div>
     );
   }
@@ -47,12 +47,12 @@ export default class NotificationsDropdown extends Dropdown {
     if (app.drawer.isOpen()) {
       this.goToRoute();
     } else {
-      this.props.state.load();
+      this.attrs.state.load();
     }
   }
 
   goToRoute() {
-    m.route(app.route('notifications'));
+    m.route.set(app.route('notifications'));
   }
 
   getUnreadCount() {

js/src/forum/components/NotificationsPage.js

@@ -6,8 +6,8 @@ import NotificationList from './NotificationList';
  * used on mobile devices where the notifications dropdown is within the drawer.
  */
 export default class NotificationsPage extends Page {
-  init() {
-    super.init();
+  oninit(vnode) {
+    super.oninit(vnode);
 
     app.history.push('notifications');
 

js/src/forum/components/Post.js

@@ -10,14 +10,16 @@ import ItemList from '../../common/utils/ItemList';
  * includes a controls dropdown; subclasses must implement `content` and `attrs`
  * methods.
  *
- * ### Props
+ * ### Attrs
  *
  * - `post`
  *
  * @abstract
  */
 export default class Post extends Component {
-  init() {
+  oninit(vnode) {
+    super.oninit(vnode);
+
     this.loading = false;
 
     /**
@@ -27,9 +29,9 @@ export default class Post extends Component {
      * @type {SubtreeRetainer}
      */
     this.subtree = new SubtreeRetainer(
-      () => this.props.post.freshness,
+      () => this.attrs.post.freshness,
       () => {
-        const user = this.props.post.user();
+        const user = this.attrs.post.user();
         return user && user.freshness;
       },
       () => this.controlsOpen
@@ -37,17 +39,14 @@ export default class Post extends Component {
   }
 
   view() {
-    const attrs = this.attrs();
+    const attrs = this.elementAttrs();
 
     attrs.className = this.classes(attrs.className).join(' ');
 
-    return (
-      <article {...attrs}>
-        {this.subtree.retain() ||
-          (() => {
-            const controls = PostControls.controls(this.props.post, this).toArray();
+    const controls = PostControls.controls(this.attrs.post, this).toArray();
 
     return (
+      <article {...attrs}>
         <div>
           {this.content()}
           <aside className="Post-actions">
@@ -75,13 +74,17 @@ export default class Post extends Component {
             <ul>{listItems(this.footerItems().toArray())}</ul>
           </footer>
         </div>
-            );
-          })()}
       </article>
     );
   }
 
-  config(isInitialized) {
+  onbeforeupdate(vnode) {
+    super.onbeforeupdate(vnode);
+
+    return this.subtree.needsRebuild();
+  }
+
+  onupdate() {
     const $actions = this.$('.Post-actions');
     const $controls = this.$('.Post-controls');
 
@@ -93,7 +96,7 @@ export default class Post extends Component {
    *
    * @return {Object}
    */
-  attrs() {
+  elementAttrs() {
     return {};
   }
 
@@ -115,8 +118,8 @@ export default class Post extends Component {
   classes(existing) {
     let classes = (existing || '').split(' ').concat(['Post']);
 
-    const user = this.props.post.user();
-    const discussion = this.props.post.discussion();
+    const user = this.attrs.post.user();
+    const discussion = this.attrs.post.discussion();
 
     if (this.loading) {
       classes.push('Post--loading');

js/src/forum/components/PostEdited.js

@@ -6,18 +6,20 @@ import extractText from '../../common/utils/extractText';
  * The `PostEdited` component displays information about when and by whom a post
  * was edited.
  *
- * ### Props
+ * ### Attrs
  *
  * - `post`
  */
 export default class PostEdited extends Component {
-  init() {
+  oninit(vnode) {
+    super.oninit(vnode);
+
     this.shouldUpdateTooltip = false;
     this.oldEditedInfo = null;
   }
 
   view() {
-    const post = this.props.post;
+    const post = this.attrs.post;
     const editedUser = post.editedUser();
     const editedInfo = extractText(app.translator.trans('core.forum.post.edited_tooltip', { user: editedUser, ago: humanTime(post.editedAt()) }));
     if (editedInfo !== this.oldEditedInfo) {
@@ -32,7 +34,17 @@ export default class PostEdited extends Component {
     );
   }
 
-  config(isInitialized) {
+  oncreate(vnode) {
+    super.oncreate(vnode);
+
+    this.rebuildTooltip();
+  }
+
+  onupdate() {
+    this.rebuildTooltip();
+  }
+
+  rebuildTooltip() {
     if (this.shouldUpdateTooltip) {
       this.$().tooltip('destroy').tooltip();
       this.shouldUpdateTooltip = false;

js/src/forum/components/PostMeta.js

@@ -7,23 +7,23 @@ import fullTime from '../../common/helpers/fullTime';
  * a dropdown containing more information about the post (number, full time,
  * permalink).
  *
- * ### Props
+ * ### Attrs
  *
  * - `post`
  */
 export default class PostMeta extends Component {
   view() {
-    const post = this.props.post;
+    const post = this.attrs.post;
     const time = post.createdAt();
     const permalink = this.getPermalink(post);
     const touch = 'ontouchstart' in document.documentElement;
 
     // When the dropdown menu is shown, select the contents of the permalink
     // input so that the user can quickly copy the URL.
-    const selectPermalink = function () {
+    const selectPermalink = function (e) {
       setTimeout(() => $(this).parent().find('.PostMeta-permalink').select());
 
-      m.redraw.strategy('none');
+      e.redraw = false;
     };
 
     return (

js/src/forum/components/PostPreview.js

@@ -7,18 +7,18 @@ import highlight from '../../common/helpers/highlight';
  * The `PostPreview` component shows a link to a post containing the avatar and
  * username of the author, and a short excerpt of the post's content.
  *
- * ### Props
+ * ### Attrs
  *
  * - `post`
  */
 export default class PostPreview extends Component {
   view() {
-    const post = this.props.post;
+    const post = this.attrs.post;
     const user = post.user();
-    const excerpt = highlight(post.contentPlain(), this.props.highlight, 300);
+    const excerpt = highlight(post.contentPlain(), this.attrs.highlight, 300);
 
     return (
-      <a className="PostPreview" href={app.route.post(post)} config={m.route} onclick={this.props.onclick}>
+      <a className="PostPreview" route={app.route.post(post)} onclick={this.attrs.onclick}>
         <span className="PostPreview-content">
           {avatar(user)}
           {username(user)} <span className="PostPreview-excerpt">{excerpt}</span>

js/src/forum/components/PostStream.js

@@ -8,7 +8,7 @@ import Button from '../../common/components/Button';
  * The `PostStream` component displays an infinitely-scrollable wall of posts in
  * a discussion. Posts that have not loaded will be displayed as placeholders.
  *
- * ### Props
+ * ### Attrs
  *
  * - `discussion`
  * - `stream`
@@ -16,9 +16,11 @@ import Button from '../../common/components/Button';
  * - `onPositionChange`
  */
 export default class PostStream extends Component {
-  init() {
-    this.discussion = this.props.discussion;
-    this.stream = this.props.stream;
+  oninit(vnode) {
+    super.oninit(vnode);
+
+    this.discussion = this.attrs.discussion;
+    this.stream = this.attrs.stream;
 
     this.scrollListener = new ScrollListener(this.onscroll.bind(this));
   }
@@ -96,29 +98,33 @@ export default class PostStream extends Component {
     return <div className="PostStream">{items}</div>;
   }
 
-  config(isInitialized, context) {
+  onupdate() {
     this.triggerScroll();
+  }
 
-    if (isInitialized) return;
+  oncreate(vnode) {
+    super.oncreate(vnode);
+
+    this.triggerScroll();
 
     // This is wrapped in setTimeout due to the following Mithril issue:
     // https://github.com/lhorie/mithril.js/issues/637
     setTimeout(() => this.scrollListener.start());
+  }
 
-    context.onunload = () => {
+  onremove() {
     this.scrollListener.stop();
     clearTimeout(this.calculatePositionTimeout);
-    };
   }
 
   /**
    * Start scrolling, if appropriate, to a newly-targeted post.
    */
   triggerScroll() {
-    if (!this.props.targetPost) return;
+    if (!this.attrs.targetPost) return;
 
     const oldTarget = this.prevTarget;
-    const newTarget = this.props.targetPost;
+    const newTarget = this.attrs.targetPost;
 
     if (oldTarget) {
       if ('number' in oldTarget && oldTarget.number === newTarget.number) return;
@@ -265,7 +271,7 @@ export default class PostStream extends Component {
     });
 
     if (startNumber) {
-      this.props.onPositionChange(startNumber || 1, endNumber, startNumber);
+      this.attrs.onPositionChange(startNumber || 1, endNumber, startNumber);
     }
   }
 
@@ -348,7 +354,7 @@ export default class PostStream extends Component {
     return Promise.all([$container.promise(), this.stream.loadPromise]).then(() => {
       this.updateScrubber();
       const index = $item.data('index');
-      m.redraw(true);
+      m.redraw.sync();
       const scroll = index == 0 ? 0 : $(`.PostStream-item[data-index=${$item.data('index')}]`).offset().top - this.getMarginTop();
       $(window).scrollTop(scroll);
       this.calculatePosition();

js/src/forum/components/PostStreamScrubber.js

@@ -7,14 +7,16 @@ import ScrollListener from '../../common/utils/ScrollListener';
  * The `PostStreamScrubber` component displays a scrubber which can be used to
  * navigate/scrub through a post stream.
  *
- * ### Props
+ * ### Attrs
  *
  * - `stream`
  * - `className`
  */
 export default class PostStreamScrubber extends Component {
-  init() {
-    this.stream = this.props.stream;
+  oninit(vnode) {
+    super.oninit(vnode);
+
+    this.stream = this.attrs.stream;
     this.handlers = {};
 
     this.scrollListener = new ScrollListener(this.updateScrubberValues.bind(this, { fromScroll: true, forceHeightChange: true }));
@@ -32,23 +34,23 @@ export default class PostStreamScrubber extends Component {
     const unreadCount = this.stream.discussion.unreadCount();
     const unreadPercent = count ? Math.min(count - this.stream.index, unreadCount) / count : 0;
 
-    function styleUnread(element, isInitialized, context) {
-      const $element = $(element);
+    function styleUnread(vnode) {
+      const $element = $(vnode.dom);
       const newStyle = {
         top: 100 - unreadPercent * 100 + '%',
         height: unreadPercent * 100 + '%',
       };
 
-      if (context.oldStyle) {
-        $element.stop(true).css(context.oldStyle).animate(newStyle);
+      if (vnode.state.oldStyle) {
+        $element.stop(true).css(vnode.state.oldStyle).animate(newStyle);
       } else {
         $element.css(newStyle);
       }
 
-      context.oldStyle = newStyle;
+      vnode.state.oldStyle = newStyle;
     }
     const classNames = ['PostStreamScrubber', 'Dropdown'];
-    if (this.props.className) classNames.push(this.props.className);
+    if (this.attrs.className) classNames.push(this.attrs.className);
 
     return (
       <div className={classNames.join(' ')}>
@@ -68,12 +70,12 @@ export default class PostStreamScrubber extends Component {
                 <div className="Scrubber-bar" />
                 <div className="Scrubber-info">
                   <strong>{viewing}</strong>
-                  <span className="Scrubber-description">{this.stream.description}</span>
+                  <span className="Scrubber-description"></span>
                 </div>
               </div>
               <div className="Scrubber-after" />
 
-              <div className="Scrubber-unread" config={styleUnread}>
+              <div className="Scrubber-unread" oncreate={styleUnread} onupdate={styleUnread}>
                 {app.translator.trans('core.forum.post_scrubber.unread_text', { count: unreadCount })}
               </div>
             </div>
@@ -87,11 +89,12 @@ export default class PostStreamScrubber extends Component {
     );
   }
 
-  config(isInitialized, context) {
+  onupdate() {
     this.stream.loadPromise.then(() => this.updateScrubberValues({ animate: true, forceHeightChange: true }));
-    if (isInitialized) return;
+  }
 
-    context.onunload = this.ondestroy.bind(this);
+  oncreate(vnode) {
+    super.oncreate(vnode);
 
     // Whenever the window is resized, adjust the height of the scrollbar
     // so that it fills the height of the sidebar.
@@ -133,6 +136,15 @@ export default class PostStreamScrubber extends Component {
       .on('mouseup touchend', (this.handlers.onmouseup = this.onmouseup.bind(this)));
 
     setTimeout(() => this.scrollListener.start());
+
+    this.updateScrubberValues({ animate: true, forceHeightChange: true });
+  }
+
+  onremove() {
+    this.scrollListener.stop();
+    $(window).off('resize', this.handlers.onresize);
+
+    $(document).off('mousemove touchmove', this.handlers.onmousemove).off('mouseup touchend', this.handlers.onmouseup);
   }
 
   /**
@@ -196,13 +208,6 @@ export default class PostStreamScrubber extends Component {
     this.updateScrubberValues({ animate: true, forceHeightChange: true });
   }
 
-  ondestroy() {
-    this.scrollListener.stop();
-    $(window).off('resize', this.handlers.onresize);
-
-    $(document).off('mousemove touchmove', this.handlers.onmousemove).off('mouseup touchend', this.handlers.onmouseup);
-  }
-
   onresize() {
     // Adjust the height of the scrollbar so that it fills the height of
     // the sidebar and doesn't overlap the footer.