Implement todo API

backend/controllers/todoController.js

@@ -0,0 +1,129 @@
+// In-memory storage
+let todos = [];
+let currentId = 1;
+
+// Get all todos
+const getAllTodos = (req, res) => {
+    res.json({
+        success: true,
+        data: todos,
+        count: todos.length
+    });
+};
+
+// Get single todo by ID
+const getTodoById = (req, res) => {
+    const id = parseInt(req.params.id);
+    const todo = todos.find(t => t.id === id);
+
+    if (!todo) {
+        return res.status(404).json({
+            success: false,
+            error: 'Todo not found'
+        });
+    }
+
+    res.json({
+        success: true,
+        data: todo
+    });
+};
+
+// Create a new todo
+const createTodo = (req, res) => {
+    const { title } = req.body;
+
+    // Title is required
+    if (!title || title.trim() === '') {
+        return res.status(400).json({
+            success: false,
+            error: 'Title is required'
+        });
+    }
+
+    const newTodo = {
+        id: currentId++,
+        title: title.trim(),
+        completed: false,
+        createdAt: new Date().toISOString()
+    };
+
+    todos.push(newTodo);
+
+    res.status(201).json({
+        success: true,
+        data: newTodo,
+        message: 'Todo created successfully'
+    });
+};
+
+// Update a todo
+const updateTodo = (req, res) => {
+    const id = parseInt(req.params.id);
+    const { title, completed } = req.body;
+
+    const todoIndex = todos.findIndex(t => t.id === id);
+
+    if (todoIndex === -1) {
+        return res.status(404).json({
+            success: false,
+            error: 'Todo not found'
+        });
+    }
+
+    // Update title if provided
+    if (title !== undefined) {
+        if (title.trim() === '') {
+            return res.status(400).json({
+                success: false,
+                error: 'Title cannot be empty'
+            });
+        }
+        todos[todoIndex].title = title.trim();
+    }
+
+    // Update completed status if provided
+    if (completed !== undefined) {
+        if (typeof completed !== 'boolean') {
+            return res.status(400).json({
+                success: false,
+                error: 'Completed must be true or false'
+            });
+        }
+        todos[todoIndex].completed = completed;
+    }
+
+    res.json({
+        success: true,
+        data: todos[todoIndex],
+        message: 'Todo updated successfully'
+    });
+};
+
+// Delete a todo
+const deleteTodo = (req, res) => {
+    const id = parseInt(req.params.id);
+    const todoIndex = todos.findIndex(t => t.id === id);
+
+    if (todoIndex === -1) {
+        return res.status(404).json({
+            success: false,
+            error: 'Todo not found'
+        });
+    }
+
+    todos.splice(todoIndex, 1);
+
+    res.json({
+        success: true,
+        message: 'Todo deleted successfully'
+    });
+};
+
+module.exports = {
+    getAllTodos,
+    getTodoById,
+    createTodo,
+    updateTodo,
+    deleteTodo
+};

backend/index.js

@@ -1,13 +1,16 @@
-const express = require("express");
+const express = require('express');
+const todoRoutes = require('./routes/todoRoutes');
+const errorHandler = require('./middleware/errorHandler');
+
 const app = express();
 const PORT = process.env.PORT || 4000;
 
-// Basic route
-app.get("/", (req, res) => {
-  res.send("Hello from Express!");
-});
+app.use(express.json());
+
+app.use('/api/todos', todoRoutes);
+
+app.use(errorHandler);
 
-// Start server
 app.listen(PORT, () => {
-  console.log(`Backend is running on http://localhost:${PORT}`);
-});
+    console.log(`Server running on http://localhost:${PORT}`);
+});

backend/middleware/errorHandler.js

@@ -0,0 +1,10 @@
+const errorHandler = (err, req, res, next) => {
+    console.error(err.stack);
+
+    res.status(500).json({
+        success: false,
+        error: 'Something went wrong on the server'
+    });
+};
+
+module.exports = errorHandler;

backend/package.json

@@ -5,6 +5,10 @@
     "start": "node index.js"
   },
   "dependencies": {
+    "cors": "^2.8.6",
     "express": "^4.18.2"
+  },
+  "devDependencies": {
+    "nodemon": "^3.1.14"
   }
 }

backend/routes/todoRoutes.js

@@ -0,0 +1,17 @@
+const express = require('express');
+const router = express.Router();
+const {
+    getAllTodos,
+    getTodoById,
+    createTodo,
+    updateTodo,
+    deleteTodo
+} = require('../controllers/todoController');
+
+router.get('/', getAllTodos);
+router.get('/:id', getTodoById);
+router.post('/', createTodo);
+router.put('/:id', updateTodo);
+router.delete('/:id', deleteTodo);
+
+module.exports = router;