From b557161917908184d77b19239ebd5251bd2be44f Mon Sep 17 00:00:00 2001
From: leonard <tamponleonard@gmail.com>
Date: Sun, 28 Jun 2026 21:42:41 +0800
Subject: [PATCH] Todo api

---
 backend/index.js        |  8 ++++
 backend/routes/todos.js | 81 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 89 insertions(+)
 create mode 100644 backend/routes/todos.js

diff --git a/backend/index.js b/backend/index.js
index ff6a6a3b..b6890a5e 100644
--- a/backend/index.js
+++ b/backend/index.js
@@ -1,12 +1,20 @@
+// file: index.js
+
 const express = require("express");
 const app = express();
 const PORT = process.env.PORT || 4000;
 
+const todosRoutes = require('./routes/todos');
+app.use(express.json()) // lets us read JSON from req.body
+
 // Basic route
 app.get("/", (req, res) => {
   res.send("Hello from Express!");
 });
 
+// all todo routes under /api/todos
+app.use('/api/todos', todosRoutes);
+
 // Start server
 app.listen(PORT, () => {
   console.log(`Backend is running on http://localhost:${PORT}`);
diff --git a/backend/routes/todos.js b/backend/routes/todos.js
new file mode 100644
index 00000000..8dfa8c23
--- /dev/null
+++ b/backend/routes/todos.js
@@ -0,0 +1,81 @@
+// file: routes/todos.js
+
+const express = require('express');
+const router = express.Router();
+
+// Data in memory
+let todos = [
+    { id: 1, title: "Todo one", completed: false, createdAt: new Date().toISOString() },
+    { id: 2, title: "Todo two", completed: false, createdAt: new Date().toISOString() }
+];
+let nextId = 3; // next id to give a todo(auto increment)
+
+// GET /api/todos - get all todos
+router.get('/', (req, res) => {
+    return res.status(200).json(todos);
+});
+
+// GET /api/todos/:id - get one todo by id
+router.get('/:id', (req, res) => {
+    const task = todos.find(task => task.id === Number(req.params.id));
+
+    // no todo with that id
+    if (!task) {
+        return res.status(404).json({ error: "Task not found."});
+    }
+
+    return res.json(task);
+});
+
+// POST /api/todos - create a new todo
+router.post('/', (req, res) => {
+    const { title } = req.body;
+
+    // check if title exist and be text
+    if (!title || typeof title !== 'string') {
+        return res.status(400).json({ error: "Title is required and title must be a string." });
+    }
+
+    // build the new todo
+    const newTask = { id: nextId++, title: title, completed: false , createdAt: new Date().toISOString() };
+
+    // save new todo
+    todos.push(newTask);
+
+    return res.status(201).json(newTask);
+});
+
+// PUT /api/todos/:id - update a todo
+router.put('/:id', (req, res) => {
+    const task = todos.find(task => task.id === Number(req.params.id));
+
+    // no todo with that id
+    if (!task) {
+        return res.status(404).json({ error: "Task not found." });
+    }
+
+    const { title, completed } = req.body;
+
+    // only update the fields that were sent
+    if (title !== undefined) task.title = title;
+    if (completed !== undefined) task.completed = completed;
+
+    return res.status(200).json(task);
+});
+
+// DELETE /api/todos/:id - delete a todo
+router.delete('/:id', (req, res) => {
+    const taskIndex = todos.findIndex(task => task.id === Number(req.params.id));
+
+    // no todo with that id
+    if (taskIndex === -1) {
+        return res.status(404).json({ error: "Task not found." });
+    }
+
+    // remove it from the array
+    const deletedTask = todos.splice(taskIndex, 1)[0];
+
+    return res.status(200).json({ message: "Task deleted", task: deletedTask });
+});
+
+module.exports = router;