From dd8dc8c4afae393ebc677c2be03fa4c1c3a96757 Mon Sep 17 00:00:00 2001
From: Morris Brodersen <mb@morrisbrodersen.de>
Date: Thu, 30 Nov 2023 11:42:02 +0100
Subject: [PATCH] refactor for pure functional business logic

---
 public/scripts/TodoApp.js                     |   9 +-
 public/scripts/TodoCustomList.js              |   8 +-
 public/scripts/TodoFrameCustom.js             |  43 +---
 public/scripts/TodoFrameDays.js               |  36 +--
 public/scripts/TodoItem.js                    |   6 +-
 public/scripts/TodoList.js                    |   2 +-
 public/scripts/TodoLogic.js                   | 212 ++++++++++++++++++
 public/scripts/TodoStore.js                   | 183 +++------------
 public/scripts/util.js                        |   9 -
 public/scripts/uuid.js                        |   8 +
 test/e2e/addCustomTodoList.test.mjs           |  12 +
 ...{addItem.test.mjs => addTodoItem.test.mjs} |   0
 test/e2e/deleteCustomTodoList.test.mjs        |  20 ++
 ...t.test.mjs => editCustomTodoList.test.mjs} |  10 -
 test/unit/TodoLogic.test.mjs                  | 143 ++++++++++++
 15 files changed, 449 insertions(+), 252 deletions(-)
 create mode 100644 public/scripts/TodoLogic.js
 create mode 100644 public/scripts/uuid.js
 create mode 100644 test/e2e/addCustomTodoList.test.mjs
 rename test/e2e/{addItem.test.mjs => addTodoItem.test.mjs} (100%)
 create mode 100644 test/e2e/deleteCustomTodoList.test.mjs
 rename test/e2e/{addCustomList.test.mjs => editCustomTodoList.test.mjs} (68%)
 create mode 100644 test/unit/TodoLogic.test.mjs

diff --git a/public/scripts/TodoApp.js b/public/scripts/TodoApp.js
index b63cb12..800d2d4 100644
--- a/public/scripts/TodoApp.js
+++ b/public/scripts/TodoApp.js
@@ -4,19 +4,14 @@ import { AppFps } from './AppFps.js';
 import { AppIcon } from './AppIcon.js';
 import { TodoFrameCustom } from './TodoFrameCustom.js';
 import { TodoFrameDays } from './TodoFrameDays.js';
+import { TodoLogic } from './TodoLogic.js';
 import { TodoStore } from './TodoStore.js';
-import { formatDateId } from './util.js';
 
 /**
  * @param {HTMLElement} el
  */
 export function TodoApp(el) {
-  let todoData = {
-    items: [],
-    customLists: [],
-    at: formatDateId(new Date()),
-    customAt: 0,
-  };
+  let todoData = TodoLogic.initTodoData();
 
   el.innerHTML = `
     <header class="app-header">
diff --git a/public/scripts/TodoCustomList.js b/public/scripts/TodoCustomList.js
index ca783a5..16580cd 100644
--- a/public/scripts/TodoCustomList.js
+++ b/public/scripts/TodoCustomList.js
@@ -82,7 +82,7 @@ export function TodoCustomList(el) {
     }
 
     el.dispatchEvent(
-      new CustomEvent('deleteTodoList', {
+      new CustomEvent('deleteCustomTodoList', {
         detail: list,
         bubbles: true,
       }),
@@ -115,15 +115,15 @@ export function TodoCustomList(el) {
     e.detail.index = e.detail.index ?? 0;
   });
 
-  el.addEventListener('todoCustomList', (e) => {
+  el.addEventListener('customTodoList', (e) => {
     list = e.detail;
     update();
   });
 
   function save() {
     el.dispatchEvent(
-      new CustomEvent('saveTodoList', {
-        detail: { list, title: inputEl.value.trim() },
+      new CustomEvent('editCustomTodoList', {
+        detail: { ...list, title: inputEl.value.trim() },
         bubbles: true,
       }),
     );
diff --git a/public/scripts/TodoFrameCustom.js b/public/scripts/TodoFrameCustom.js
index 04b3533..294211a 100644
--- a/public/scripts/TodoFrameCustom.js
+++ b/public/scripts/TodoFrameCustom.js
@@ -1,16 +1,13 @@
 import { AppIcon } from './AppIcon.js';
 import { AppSortable } from './AppSortable.js';
 import { TodoCustomList } from './TodoCustomList.js';
+import { TodoLogic } from './TodoLogic.js';
 
 /**
  * @param {HTMLElement} el
  */
 export function TodoFrameCustom(el) {
-  let todoData = {
-    customLists: [],
-    items: [],
-    customAt: 0,
-  };
+  let todoData = TodoLogic.initTodoData();
 
   el.innerHTML = `
     <div class="leftcontrols">
@@ -42,9 +39,7 @@ export function TodoFrameCustom(el) {
   );
 
   el.querySelector('.add').addEventListener('click', () => {
-    el.dispatchEvent(
-      new CustomEvent('addTodoList', { detail: {}, bubbles: true }),
-    );
+    el.dispatchEvent(new CustomEvent('addCustomTodoList', { bubbles: true }));
     // TODO seek if not at end
   });
 
@@ -52,9 +47,9 @@ export function TodoFrameCustom(el) {
     if (!e.detail.data.list) return;
 
     el.dispatchEvent(
-      new CustomEvent('moveTodoList', {
+      new CustomEvent('moveCustomTodoList', {
         detail: {
-          list: e.detail.data.list,
+          ...e.detail.data.list,
           index: e.detail.index,
         },
         bubbles: true,
@@ -63,9 +58,7 @@ export function TodoFrameCustom(el) {
   });
 
   el.addEventListener('draggableOver', (e) => {
-    if (!e.detail.data.list) return;
-
-    updatePositions();
+    if (e.detail.data.list) updatePositions();
   });
 
   el.addEventListener('todoData', (e) => {
@@ -74,14 +67,15 @@ export function TodoFrameCustom(el) {
   });
 
   function update() {
-    const lists = getLists();
+    const customLists = TodoLogic.getCustomTodoLists(todoData);
+
     const container = el.querySelector('.container');
     const obsolete = new Set(container.children);
     const childrenByKey = new Map();
 
     obsolete.forEach((child) => childrenByKey.set(child.dataset.key, child));
 
-    const children = lists.map((list) => {
+    const children = customLists.map((list) => {
       let child = childrenByKey.get(list.id);
 
       if (child) {
@@ -93,7 +87,7 @@ export function TodoFrameCustom(el) {
         TodoCustomList(child);
       }
 
-      child.dispatchEvent(new CustomEvent('todoCustomList', { detail: list }));
+      child.dispatchEvent(new CustomEvent('customTodoList', { detail: list }));
 
       return child;
     });
@@ -136,21 +130,4 @@ export function TodoFrameCustom(el) {
     // Update collapsible on changing heights
     el.dispatchEvent(new CustomEvent('collapse', { bubbles: true }));
   }
-
-  function getLists() {
-    return todoData.customLists
-      .map((list) => ({
-        id: list.id,
-        index: list.index,
-        title: list.title,
-        items: getItemsForList(list.id),
-      }))
-      .sort((a, b) => a.index - b.index);
-  }
-
-  function getItemsForList(listId) {
-    return todoData.items
-      .filter((item) => item.listId === listId)
-      .sort((a, b) => a.index - b.index);
-  }
 }
diff --git a/public/scripts/TodoFrameDays.js b/public/scripts/TodoFrameDays.js
index af598cd..72c3f80 100644
--- a/public/scripts/TodoFrameDays.js
+++ b/public/scripts/TodoFrameDays.js
@@ -1,18 +1,14 @@
 import { AppDatePicker } from './AppDatePicker.js';
 import { AppIcon } from './AppIcon.js';
 import { TodoDay } from './TodoDay.js';
-import { formatDateId } from './util.js';
+import { TodoLogic } from './TodoLogic.js';
 
 /**
  * @param {HTMLElement} el
  */
 export function TodoFrameDays(el) {
   const RANGE = 14;
-
-  let todoData = {
-    items: [],
-    at: formatDateId(new Date()),
-  };
+  let todoData = TodoLogic.initTodoData();
 
   el.innerHTML = `
     <nav class="leftcontrols">
@@ -100,7 +96,7 @@ export function TodoFrameDays(el) {
   });
 
   function update() {
-    const days = getDays();
+    const listsByDay = TodoLogic.getTodoListsByDay(todoData, RANGE);
 
     const container = el.querySelector('.container');
     const obsolete = new Set(container.children);
@@ -108,7 +104,7 @@ export function TodoFrameDays(el) {
 
     obsolete.forEach((child) => childrenByKey.set(child.dataset.key, child));
 
-    const children = days.map((day) => {
+    const children = listsByDay.map((day) => {
       let child = childrenByKey.get(day.id);
 
       if (child) {
@@ -147,28 +143,4 @@ export function TodoFrameDays(el) {
 
     el.style.height = `${height + 50}px`;
   }
-
-  function getDays() {
-    const days = [];
-
-    for (let i = 0; i < 2 * RANGE; ++i) {
-      const t = new Date(todoData.at);
-      t.setDate(t.getDate() - RANGE + i);
-      const id = formatDateId(t);
-
-      days.push({
-        id,
-        items: getItemsForDay(id),
-        position: -RANGE + i,
-      });
-    }
-
-    return days;
-  }
-
-  function getItemsForDay(dateId) {
-    return todoData.items
-      .filter((item) => item.listId === dateId)
-      .sort((a, b) => a.index - b.index);
-  }
 }
diff --git a/public/scripts/TodoItem.js b/public/scripts/TodoItem.js
index 9451202..9beadfd 100644
--- a/public/scripts/TodoItem.js
+++ b/public/scripts/TodoItem.js
@@ -50,7 +50,7 @@ export function TodoItem(el) {
     el.dispatchEvent(
       new CustomEvent('checkTodoItem', {
         detail: {
-          item,
+          ...item,
           done: !item.done,
         },
         bubbles: true,
@@ -121,9 +121,9 @@ export function TodoItem(el) {
     }
 
     el.dispatchEvent(
-      new CustomEvent('saveTodoItem', {
+      new CustomEvent('editTodoItem', {
         detail: {
-          item,
+          ...item,
           label,
         },
         bubbles: true,
diff --git a/public/scripts/TodoList.js b/public/scripts/TodoList.js
index 2e856ce..bbcdee8 100644
--- a/public/scripts/TodoList.js
+++ b/public/scripts/TodoList.js
@@ -20,7 +20,7 @@ export function TodoList(el) {
     el.dispatchEvent(
       new CustomEvent('moveTodoItem', {
         detail: {
-          item: e.detail.data.item,
+          ...e.detail.data.item,
           index: e.detail.index,
         },
         bubbles: true,
diff --git a/public/scripts/TodoLogic.js b/public/scripts/TodoLogic.js
new file mode 100644
index 0000000..f256693
--- /dev/null
+++ b/public/scripts/TodoLogic.js
@@ -0,0 +1,212 @@
+import { formatDateId } from './util.js';
+import { uuid } from './uuid.js';
+
+export class TodoLogic {
+  static initTodoData(now = new Date()) {
+    return {
+      items: [],
+      customLists: [],
+      at: formatDateId(now),
+      customAt: 0,
+    };
+  }
+
+  static getTodoListsByDay(data, range) {
+    const listsByDay = [];
+
+    for (let i = 0; i < 2 * range; ++i) {
+      const t = new Date(data.at);
+      t.setDate(t.getDate() - range + i);
+      const id = formatDateId(t);
+
+      listsByDay.push({
+        id,
+        items: TodoLogic.getTodoItemsForList(data, id),
+        position: -range + i,
+      });
+    }
+
+    return listsByDay;
+  }
+
+  static getTodoItemsForList(data, listId) {
+    return data.items
+      .filter((item) => item.listId === listId)
+      .sort((a, b) => a.index - b.index);
+  }
+
+  static addTodoItem(data, input) {
+    let index = 0;
+
+    for (const item of data.items) {
+      if (item.listId === input.listId) {
+        index = Math.max(index, item.index + 1);
+      }
+    }
+
+    return {
+      ...data,
+      items: [
+        ...data.items,
+        {
+          ...input,
+          id: uuid(),
+          index,
+          done: false,
+        },
+      ],
+    };
+  }
+
+  static checkTodoItem(data, input) {
+    return {
+      ...data,
+      items: data.items.map((item) =>
+        item.id === input.id ? { ...item, done: input.done } : item,
+      ),
+    };
+  }
+
+  static editTodoItem(data, input) {
+    return {
+      ...data,
+      items: data.items.map((item) =>
+        item.id === input.id ? { ...item, label: input.label } : item,
+      ),
+    };
+  }
+
+  static moveTodoItem(data, input) {
+    const itemToMove = data.items.find((item) => item.id === input.id);
+
+    // Reinsert item at target list and index
+    let list = data.items.filter(
+      (item) => item.listId === input.listId && item.id !== input.id,
+    );
+    list.splice(input.index, 0, { ...itemToMove, listId: input.listId });
+    list = TodoLogic.setIndexes(list);
+
+    // Reinsert updated list
+    let items = data.items.filter(
+      (item) => item.listId !== input.listId && item.id !== input.id,
+    );
+    items = [...items, ...list];
+
+    return {
+      ...data,
+      items,
+    };
+  }
+
+  static deleteTodoItem(data, input) {
+    return {
+      ...data,
+      items: data.items.filter((item) => item.id !== input.id),
+    };
+  }
+
+  //
+
+  static getCustomTodoLists(data) {
+    return data.customLists
+      .map((list) => ({
+        id: list.id,
+        index: list.index,
+        title: list.title,
+        items: TodoLogic.getTodoItemsForList(data, list.id),
+      }))
+      .sort((a, b) => a.index - b.index);
+  }
+
+  static addCustomTodoList(data) {
+    let index = 0;
+
+    for (const customList of data.customLists) {
+      index = Math.max(index, customList.index + 1);
+    }
+
+    return {
+      ...data,
+      customLists: [
+        ...data.customLists,
+        {
+          id: uuid(),
+          index,
+          title: '',
+        },
+      ],
+    };
+  }
+
+  static editCustomTodoList(data, input) {
+    return {
+      ...data,
+      customLists: data.customLists.map((customList) =>
+        customList.id === input.id
+          ? { ...customList, title: input.title }
+          : customList,
+      ),
+    };
+  }
+
+  static moveCustomTodoList(data, input) {
+    const customListToMove = data.customLists.find(
+      (customList) => customList.id === input.id,
+    );
+
+    let customLists = data.customLists
+      .filter((customList) => customList.id !== input.id)
+      .sort((a, b) => a.index - b.index);
+    customLists.splice(input.index, 0, customListToMove);
+    customLists = TodoLogic.setIndexes(customLists);
+
+    return {
+      ...data,
+      customLists,
+    };
+  }
+
+  static deleteCustomTodoList(data, input) {
+    return {
+      ...data,
+      customLists: data.customLists.filter(
+        (customList) => customList.id !== input.id,
+      ),
+    };
+  }
+
+  //
+
+  static seekDays(data, delta) {
+    const t = new Date(`${data.at}T00:00:00`);
+    t.setDate(t.getDate() + delta);
+
+    return { ...data, at: formatDateId(t) };
+  }
+
+  static seekToToday(data) {
+    return { ...data, at: formatDateId(new Date()) };
+  }
+
+  static seekToDate(data, date) {
+    return { ...data, at: formatDateId(date) };
+  }
+
+  static seekCustomTodoLists(data, delta) {
+    return {
+      ...data,
+      customAt: Math.max(
+        0,
+        Math.min(data.customLists.length - 1, data.customAt + delta),
+      ),
+    };
+  }
+
+  //
+
+  static setIndexes(array) {
+    return array.map((item, index) =>
+      item.index === index ? item : { ...item, index },
+    );
+  }
+}
diff --git a/public/scripts/TodoStore.js b/public/scripts/TodoStore.js
index c044016..4a77ce6 100644
--- a/public/scripts/TodoStore.js
+++ b/public/scripts/TodoStore.js
@@ -1,158 +1,36 @@
-import { formatDateId, uuid } from './util.js';
+import { TodoLogic } from './TodoLogic.js';
 
 /**
  * @param {HTMLElement} el
  */
 export function TodoStore(el) {
-  const todoData = {
-    items: [],
-    customLists: [],
-    at: formatDateId(new Date()),
-    customAt: 0,
-  };
-
-  let storeTimeout;
+  let todoData = TodoLogic.initTodoData();
+  let saveTimeout;
 
   el.addEventListener('loadTodoStore', load);
 
-  el.addEventListener('addTodoItem', (e) => {
-    let index = 0;
-
-    for (const item of todoData.items) {
-      if (item.listId === e.detail.listId) {
-        index = Math.max(index, item.index + 1);
-      }
-    }
-
-    todoData.items.push({
-      id: uuid(),
-      listId: e.detail.listId,
-      index,
-      label: e.detail.label,
-      done: false,
+  for (const action of [
+    'addTodoItem',
+    'checkTodoItem',
+    'editTodoItem',
+    'moveTodoItem',
+    'deleteTodoItem',
+    'addCustomTodoList',
+    'editCustomTodoList',
+    'moveCustomTodoList',
+    'deleteCustomTodoList',
+    'seekDays',
+    'seekToToday',
+    'seekToDate',
+    'seekCustomTodoLists',
+  ]) {
+    el.addEventListener(action, (e) => {
+      todoData = TodoLogic[action](todoData, e.detail);
+      update();
     });
+  }
 
-    dispatch({ items: todoData.items });
-  });
-
-  el.addEventListener('checkTodoItem', (e) => {
-    if (e.detail.item.done === e.detail.done) return;
-
-    e.detail.item.done = e.detail.done;
-    dispatch({ items: todoData.items });
-  });
-
-  el.addEventListener('saveTodoItem', (e) => {
-    if (e.detail.item.label === e.detail.label) return;
-
-    e.detail.item.label = e.detail.label;
-    dispatch({ items: todoData.items });
-  });
-
-  el.addEventListener('moveTodoItem', (e) => {
-    const movedItem = todoData.items.find(
-      (item) => item.id === e.detail.item.id,
-    );
-
-    const listItems = todoData.items.filter(
-      (item) => item.listId === e.detail.listId && item !== movedItem,
-    );
-
-    listItems.sort((a, b) => a.index - b.index);
-
-    movedItem.listId = e.detail.listId;
-    listItems.splice(e.detail.index, 0, movedItem);
-
-    listItems.forEach((item, index) => {
-      item.index = index;
-    });
-
-    dispatch({ items: todoData.items });
-  });
-
-  el.addEventListener('deleteTodoItem', (e) =>
-    dispatch({
-      items: todoData.items.filter((item) => item.id !== e.detail.id),
-    }),
-  );
-
-  el.addEventListener('addTodoList', (e) => {
-    let index = 0;
-
-    for (const customList of todoData.customLists) {
-      index = Math.max(index, customList.index + 1);
-    }
-
-    todoData.customLists.push({
-      id: uuid(),
-      index,
-      title: e.detail.title || '',
-    });
-
-    dispatch({ customLists: todoData.customLists });
-  });
-
-  el.addEventListener('saveTodoList', (e) => {
-    const list = todoData.customLists.find((l) => l.id === e.detail.list.id);
-
-    if (list.title === e.detail.title) return;
-
-    list.title = e.detail.title;
-
-    dispatch({ customLists: todoData.customLists });
-  });
-
-  el.addEventListener('moveTodoList', (e) => {
-    const movedListIndex = todoData.customLists.findIndex(
-      (list) => list.id === e.detail.list.id,
-    );
-    const movedList = todoData.customLists[movedListIndex];
-
-    todoData.customLists.splice(movedListIndex, 1);
-    todoData.customLists.sort((a, b) => a.index - b.index);
-    todoData.customLists.splice(e.detail.index, 0, movedList);
-
-    todoData.customLists.forEach((item, index) => {
-      item.index = index;
-    });
-
-    dispatch({ customLists: todoData.customLists });
-  });
-
-  el.addEventListener('deleteTodoList', (e) =>
-    dispatch({
-      customLists: todoData.customLists.filter(
-        (customList) => customList.id !== e.detail.id,
-      ),
-    }),
-  );
-
-  el.addEventListener('seekDays', (e) => {
-    const t = new Date(`${todoData.at}T00:00:00`);
-    t.setDate(t.getDate() + e.detail);
-
-    dispatch({ at: formatDateId(t) });
-  });
-
-  el.addEventListener('seekToToday', () =>
-    dispatch({ at: formatDateId(new Date()) }),
-  );
-
-  el.addEventListener('seekToDate', (e) =>
-    dispatch({ at: formatDateId(e.detail) }),
-  );
-
-  el.addEventListener('seekCustomTodoLists', (e) =>
-    dispatch({
-      customAt: Math.max(
-        0,
-        Math.min(todoData.customLists.length - 1, todoData.customAt + e.detail),
-      ),
-    }),
-  );
-
-  function dispatch(next) {
-    Object.assign(todoData, next);
+  function update() {
     save();
 
     el.dispatchEvent(
@@ -164,23 +42,22 @@ export function TodoStore(el) {
   }
 
   function load() {
-    if (!localStorage || !localStorage.todo) {
-      dispatch(todoData);
-      return;
-    }
-
     try {
-      dispatch(JSON.parse(localStorage.todo));
+      if (localStorage?.todo) {
+        todoData = { ...todoData, ...JSON.parse(localStorage.todo) };
+      }
     } catch (err) {
       // eslint-disable-next-line no-console
       console.warn(err);
     }
+
+    update();
   }
 
   function save() {
-    clearTimeout(storeTimeout);
+    clearTimeout(saveTimeout);
 
-    storeTimeout = setTimeout(() => {
+    saveTimeout = setTimeout(() => {
       try {
         localStorage.todo = JSON.stringify(todoData);
       } catch (err) {
diff --git a/public/scripts/util.js b/public/scripts/util.js
index 0388ca1..4f61169 100644
--- a/public/scripts/util.js
+++ b/public/scripts/util.js
@@ -1,12 +1,3 @@
-export function uuid() {
-  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
-    const r = (Math.random() * 16) | 0,
-      v = c == 'x' ? r : (r & 0x3) | 0x8;
-
-    return v.toString(16);
-  });
-}
-
 /**
  * @param {Date} date
  * @returns {string}
diff --git a/public/scripts/uuid.js b/public/scripts/uuid.js
new file mode 100644
index 0000000..facb369
--- /dev/null
+++ b/public/scripts/uuid.js
@@ -0,0 +1,8 @@
+export function uuid() {
+  return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
+    const r = (Math.random() * 16) | 0,
+      v = c === 'x' ? r : (r & 0x3) | 0x8;
+
+    return v.toString(16);
+  });
+}
diff --git a/test/e2e/addCustomTodoList.test.mjs b/test/e2e/addCustomTodoList.test.mjs
new file mode 100644
index 0000000..f622bf0
--- /dev/null
+++ b/test/e2e/addCustomTodoList.test.mjs
@@ -0,0 +1,12 @@
+import { expect, test } from '@playwright/test';
+import '../coverage.mjs';
+
+test('Add custom to-do list', async ({ page }) => {
+  await page.goto('http://localhost:8080');
+
+  const add = page.locator('.todo-frame.-custom .add');
+  await add.click();
+
+  const title = page.locator('.todo-custom-list > .header > .title');
+  await expect(title).toHaveText('...');
+});
diff --git a/test/e2e/addItem.test.mjs b/test/e2e/addTodoItem.test.mjs
similarity index 100%
rename from test/e2e/addItem.test.mjs
rename to test/e2e/addTodoItem.test.mjs
diff --git a/test/e2e/deleteCustomTodoList.test.mjs b/test/e2e/deleteCustomTodoList.test.mjs
new file mode 100644
index 0000000..4f27452
--- /dev/null
+++ b/test/e2e/deleteCustomTodoList.test.mjs
@@ -0,0 +1,20 @@
+import { expect, test } from '@playwright/test';
+import '../coverage.mjs';
+
+test('Delete custom to-do list', async ({ page }) => {
+  await page.goto('http://localhost:8080');
+
+  const add = page.locator('.todo-frame.-custom .add');
+  await add.click();
+
+  const title = page.locator('.todo-custom-list > .header > .title');
+  await title.click();
+
+  const button = page.locator('.todo-custom-list  > .header > .form > .delete');
+
+  await expect(button).toBeVisible();
+
+  await button.click();
+
+  await expect(title).not.toBeAttached();
+});
diff --git a/test/e2e/addCustomList.test.mjs b/test/e2e/editCustomTodoList.test.mjs
similarity index 68%
rename from test/e2e/addCustomList.test.mjs
rename to test/e2e/editCustomTodoList.test.mjs
index 32810d7..2737773 100644
--- a/test/e2e/addCustomList.test.mjs
+++ b/test/e2e/editCustomTodoList.test.mjs
@@ -1,16 +1,6 @@
 import { expect, test } from '@playwright/test';
 import '../coverage.mjs';
 
-test('Add custom to-do list', async ({ page }) => {
-  await page.goto('http://localhost:8080');
-
-  const add = page.locator('.todo-frame.-custom .add');
-  await add.click();
-
-  const title = page.locator('.todo-custom-list > .header > .title');
-  await expect(title).toHaveText('...');
-});
-
 test('Edit custom to-do list title (Enter)', async ({ page }) => {
   await page.goto('http://localhost:8080');
 
diff --git a/test/unit/TodoLogic.test.mjs b/test/unit/TodoLogic.test.mjs
new file mode 100644
index 0000000..046139b
--- /dev/null
+++ b/test/unit/TodoLogic.test.mjs
@@ -0,0 +1,143 @@
+import { expect, test } from '@playwright/test';
+import TodoLogicModule from '../../public/scripts/TodoLogic.js';
+import '../coverage.mjs';
+
+const { TodoLogic } = TodoLogicModule;
+
+test('TodoLogic.initTodoData', () => {
+  const data = TodoLogic.initTodoData(new Date(0));
+
+  expect(data).toEqual({
+    at: '1970-01-01',
+    customAt: 0,
+    customLists: [],
+    items: [],
+  });
+});
+
+test('TodoLogic.addTodoItem', () => {
+  let data = TodoLogic.initTodoData(new Date(0));
+
+  data = TodoLogic.addTodoItem(data, { label: 'foo', listId: '1970-01-01' });
+
+  expect(data).toEqual({
+    at: '1970-01-01',
+    customAt: 0,
+    customLists: [],
+    items: [
+      {
+        id: expect.stringMatching(/./),
+        listId: '1970-01-01',
+        label: 'foo',
+        index: 0,
+        done: false,
+      },
+    ],
+  });
+
+  data = TodoLogic.addTodoItem(data, { label: 'bar', listId: '1970-01-01' });
+
+  expect(data.items).toEqual([
+    {
+      id: expect.stringMatching(/./),
+      listId: '1970-01-01',
+      label: 'foo',
+      index: 0,
+      done: false,
+    },
+    {
+      id: expect.stringMatching(/./),
+      listId: '1970-01-01',
+      label: 'bar',
+      index: 1,
+      done: false,
+    },
+  ]);
+
+  data = TodoLogic.addTodoItem(data, { label: 'baz', listId: '1970-01-02' });
+
+  expect(data.items).toEqual([
+    {
+      id: expect.stringMatching(/./),
+      listId: '1970-01-01',
+      label: 'foo',
+      index: 0,
+      done: false,
+    },
+    {
+      id: expect.stringMatching(/./),
+      listId: '1970-01-01',
+      label: 'bar',
+      index: 1,
+      done: false,
+    },
+    {
+      id: expect.stringMatching(/./),
+      listId: '1970-01-02',
+      label: 'baz',
+      index: 0,
+      done: false,
+    },
+  ]);
+});
+
+test('TodoLogic.moveTodoItem', () => {
+  let data = TodoLogic.initTodoData(new Date(0));
+
+  data = {
+    ...data,
+    items: [
+      {
+        id: 'a',
+        listId: '1970-01-01',
+        label: 'foo',
+        index: 0,
+        done: false,
+      },
+      {
+        id: 'b',
+        listId: '1970-01-01',
+        label: 'bar',
+        index: 1,
+        done: false,
+      },
+      {
+        id: 'c',
+        listId: '1970-01-02',
+        label: 'baz',
+        index: 0,
+        done: false,
+      },
+    ],
+  };
+
+  data = TodoLogic.moveTodoItem(data, {
+    id: 'a',
+    listId: '1970-01-01',
+    index: 1,
+  });
+
+  expect(data.items).toEqual([
+    {
+      id: 'c',
+      listId: '1970-01-02',
+      label: 'baz',
+      index: 0,
+      done: false,
+    },
+    {
+      id: 'b',
+      listId: '1970-01-01',
+      label: 'bar',
+      index: 0,
+      done: false,
+    },
+    {
+      id: 'a',
+      listId: '1970-01-01',
+      label: 'foo',
+      index: 1,
+      done: false,
+    },
+  ]);
+});