Extract ModalManagerState from ModalManager (#2162)

js/src/common/components/Modal.js

@@ -9,6 +9,11 @@ import Button from './Button';
  * @abstract
  */
 export default class Modal extends Component {
+  /**
+   * Determine whether or not the modal should be dismissible via an 'x' button.
+   */
+  static isDismissible = true;
+
   init() {
     /**
      * Attributes for an alert component to show below the header.
@@ -18,6 +23,16 @@ export default class Modal extends Component {
     this.alertAttrs = null;
   }
 
+  config(isInitialized, context) {
+    if (isInitialized) return;
+
+    this.props.onshow(() => this.onready());
+
+    context.onunload = () => {
+      this.props.onhide();
+    };
+  }
+
   view() {
     if (this.alertAttrs) {
       this.alertAttrs.dismissible = false;
@@ -26,7 +41,7 @@ export default class Modal extends Component {
     return (
       <div className={'Modal modal-dialog ' + this.className()}>
         <div className="Modal-content">
-          {this.isDismissible() ? (
+          {this.constructor.isDismissible ? (
             <div className="Modal-close App-backControl">
               {Button.component({
                 icon: 'fas fa-times',
@@ -52,15 +67,6 @@ export default class Modal extends Component {
     );
   }
 
-  /**
-   * Determine whether or not the modal should be dismissible via an 'x' button.
-   *
-   * @return {Boolean}
-   */
-  isDismissible() {
-    return true;
-  }
-
   /**
    * Get the class name to apply to the modal.
    *
@@ -105,7 +111,7 @@ export default class Modal extends Component {
    * Hide the modal.
    */
   hide() {
-    app.modal.close();
+    this.props.onhide();
   }
 
   /**