algorithm-conduction · algorithm-conduction · Apr 3, 2026
diff --git a/.gitignore b/.gitignore
@@ -0,0 +1,2 @@
+node_modules/
+package-lock.json
diff --git a/package.json b/package.json
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+{
+  "name": "todo-app",
+  "version": "1.0.0",
+  "description": "Minimal TODO app — REST API with in-memory store and vanilla JS frontend",
+  "type": "module",
+  "main": "src/server.js",
+  "scripts": {
+    "start": "node src/server.js",
+    "test": "vitest run"
+  },
+  "dependencies": {
+    "express": "^4.18.2"
+  },
+  "devDependencies": {
+    "supertest": "^6.3.4",
+    "vitest": "^1.6.0"
+  },
+  "license": "EUPL-1.2"
+}
diff --git a/public/index.html b/public/index.html
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+<!--
+  SPDX-License-Identifier: EUPL-1.2
+  Copyright (C) 2026 Conduction B.V.
+-->
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8" />
+  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  <title>Todo App</title>
+  <style>
+    body { font-family: sans-serif; max-width: 600px; margin: 2rem auto; padding: 0 1rem; }
+    h1 { font-size: 1.5rem; }
+    form { display: flex; gap: 0.5rem; margin-bottom: 1rem; }
+    input[type="text"] { flex: 1; padding: 0.4rem; font-size: 1rem; }
+    button { padding: 0.4rem 0.8rem; cursor: pointer; }
+    ul { list-style: none; padding: 0; }
+    li { display: flex; align-items: center; gap: 0.5rem; padding: 0.4rem 0; border-bottom: 1px solid #eee; }
+    li.completed span { text-decoration: line-through; color: #888; }
+    .del { margin-left: auto; color: #c00; background: none; border: none; font-size: 1rem; cursor: pointer; }
+  </style>
+</head>
+<body>
+  <h1>Todo App</h1>
+  <form id="add-form">
+    <input type="text" id="title-input" placeholder="New todo…" required />
+    <button type="submit">Add</button>
+  </form>
+  <ul id="todo-list"></ul>
+
+  <script>
+    const list = document.getElementById('todo-list');
+    const form = document.getElementById('add-form');
+    const titleInput = document.getElementById('title-input');
+
+    async function loadTodos() {
+      const res = await fetch('/api/todos');
+      const todos = await res.json();
+      list.innerHTML = '';
+      todos.forEach(renderTodo);
+    }
+
+    function renderTodo(todo) {
+      const li = document.createElement('li');
+      if (todo.completed) li.classList.add('completed');
+
+      const cb = document.createElement('input');
+      cb.type = 'checkbox';
+      cb.checked = todo.completed;
+      cb.addEventListener('change', () => toggleTodo(todo.id, cb.checked));
+
+      const span = document.createElement('span');
+      span.textContent = todo.title;
+
+      const del = document.createElement('button');
+      del.className = 'del';
+      del.textContent = '✕';
+      del.addEventListener('click', () => deleteTodo(todo.id));
+
+      li.append(cb, span, del);
+      list.appendChild(li);
+    }
+
+    form.addEventListener('submit', async (e) => {
+      e.preventDefault();
+      const title = titleInput.value.trim();
+      if (!title) return;
+      await fetch('/api/todos', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ title }),
+      });
+      titleInput.value = '';
+      loadTodos();
+    });
+
+    async function toggleTodo(id, completed) {
+      await fetch(`/api/todos/${id}`, {
+        method: 'PATCH',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ completed }),
+      });
+      loadTodos();
+    }
+
+    async function deleteTodo(id) {
+      await fetch(`/api/todos/${id}`, { method: 'DELETE' });
+      loadTodos();
+    }
+
+    loadTodos();
+  </script>
+</body>
+</html>
diff --git a/src/server.js b/src/server.js
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+// SPDX-License-Identifier: EUPL-1.2
+// Copyright (C) 2026 Conduction B.V.
+
+import express from 'express';
+import { list, create, update, remove } from './store.js';
+
+const app = express();
+app.use(express.json());
+app.use(express.static('public'));
+
+// GET /api/todos — list all todos
+app.get('/api/todos', (req, res) => {
+  res.json(list());
+});
+
+// POST /api/todos — create a todo
+app.post('/api/todos', (req, res) => {
+  const { title } = req.body;
+  if (!title || typeof title !== 'string') {
+    return res.status(400).json({ error: 'title is required' });
+  }
+  const todo = create(title);
+  res.status(201).json(todo);
+});
+
+// PATCH /api/todos/:id — update a todo
+app.patch('/api/todos/:id', (req, res) => {
+  const id = parseInt(req.params.id, 10);
+  const { completed } = req.body;
+  const todo = update(id, { completed });
+  if (!todo) return res.status(404).json({ error: 'not found' });
+  res.json(todo);
+});
+
+// DELETE /api/todos/:id — delete a todo
+app.delete('/api/todos/:id', (req, res) => {
+  const id = parseInt(req.params.id, 10);
+  const removed = remove(id);
+  if (!removed) return res.status(404).json({ error: 'not found' });
+  res.status(204).send();
+});
+
+export default app;
diff --git a/src/store.js b/src/store.js
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+// SPDX-License-Identifier: EUPL-1.2
+// Copyright (C) 2026 Conduction B.V.
+
+let todos = [];
+let nextId = 1;
+
+function list() {
+  return todos;
+}
+
+function create(title) {
+  const todo = { id: nextId++, title, completed: false };
+  todos.push(todo);
+  return todo;
+}
+
+function update(id, fields) {
+  const todo = todos.find((t) => t.id === id);
+  if (!todo) return null;
+  Object.assign(todo, fields);
+  return todo;
+}
+
+function remove(id) {
+  const index = todos.findIndex((t) => t.id === id);
+  if (index === -1) return false;
+  todos.splice(index, 1);
+  return true;
+}
+
+function reset() {
+  todos = [];
+  nextId = 1;
+}
+
+export { list, create, update, remove, reset };
+export default { list, create, update, remove, reset };
diff --git a/test/api.test.js b/test/api.test.js
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+// SPDX-License-Identifier: EUPL-1.2
+// Copyright (C) 2026 Conduction B.V.
+
+import { describe, it, beforeEach, expect } from 'vitest';
+import request from 'supertest';
+import app from '../src/server.js';
+import store from '../src/store.js';
+
+beforeEach(() => {
+  store.reset();
+});
+
+describe('POST /api/todos', () => {
+  it('creates a todo and returns 201 with id, title, completed=false', async () => {
+    const res = await request(app)
+      .post('/api/todos')
+      .send({ title: 'Buy milk' });
+
+    expect(res.status).toBe(201);
+    expect(res.body).toMatchObject({ title: 'Buy milk', completed: false });
+    expect(typeof res.body.id).toBe('number');
+  });
+
+  it('returns 400 when title is missing', async () => {
+    const res = await request(app).post('/api/todos').send({});
+    expect(res.status).toBe(400);
+  });
+});
+
+describe('GET /api/todos', () => {
+  it('returns 200 with an array containing created todos', async () => {
+    store.create('Buy milk');
+
+    const res = await request(app).get('/api/todos');
+
+    expect(res.status).toBe(200);
+    expect(Array.isArray(res.body)).toBe(true);
+    expect(res.body).toHaveLength(1);
+    expect(res.body[0]).toMatchObject({ title: 'Buy milk', completed: false });
+  });
+
+  it('returns empty array when no todos exist', async () => {
+    const res = await request(app).get('/api/todos');
+    expect(res.status).toBe(200);
+    expect(res.body).toEqual([]);
+  });
+});
+
+describe('PATCH /api/todos/:id', () => {
+  it('marks a todo as completed and returns 200', async () => {
+    const todo = store.create('Buy milk');
+
+    const res = await request(app)
+      .patch(`/api/todos/${todo.id}`)
+      .send({ completed: true });
+
+    expect(res.status).toBe(200);
+    expect(res.body.completed).toBe(true);
+  });
+
+  it('returns 404 for non-existent todo', async () => {
+    const res = await request(app)
+      .patch('/api/todos/999')
+      .send({ completed: true });
+    expect(res.status).toBe(404);
+  });
+});
+
+describe('DELETE /api/todos/:id', () => {
+  it('deletes a todo and returns 204', async () => {
+    const todo = store.create('Buy milk');
+
+    const res = await request(app).delete(`/api/todos/${todo.id}`);
+    expect(res.status).toBe(204);
+
+    const listRes = await request(app).get('/api/todos');
+    expect(listRes.body).toEqual([]);
+  });
+
+  it('returns 404 for non-existent todo', async () => {
+    const res = await request(app).delete('/api/todos/999');
+    expect(res.status).toBe(404);
+  });
+});