JSON API Tutorial - Simple Guide

const express = require('express');
const app = express();
const PORT = 3000;
// Middleware to parse JSON requests
app.use(express.json());
// Sample data
let users = [
  { id: 1, name: 'John Doe', email: 'john@example.com' },
  { id: 2, name: 'Jane Smith', email: 'jane@example.com' },
  { id: 3, name: 'Bob Johnson', email: 'bob@example.com' }
];
let posts = [
  { id: 1, title: 'First Post', content: 'This is the first post', userId: 1 },
  { id: 2, title: 'Second Post', content: 'This is the second post', userId: 2 }
];
// Routes
app.get('/', (req, res) => {
  res.json({ 
    message: 'Welcome to Simple JSON API',
    endpoints: [
      'GET /users - Get all users',
      'GET /users/:id - Get user by ID',
      'POST /users - Create new user',
      'GET /posts - Get all posts',
      'GET /posts/:id - Get post by ID'
    ]
  });
});
// GET all users
app.get('/users', (req, res) => {
  res.json({
    success: true,
    data: users,
    count: users.length
  });
});
// GET user by ID
app.get('/users/:id', (req, res) => {
  const id = parseInt(req.params.id);
  const user = users.find(u => u.id === id);
  
  if (!user) {
    return res.status(404).json({
      success: false,
      message: 'User not found'
    });
  }
  
  res.json({
    success: true,
    data: user
  });
});
// POST create new user
app.post('/users', (req, res) => {
  const { name, email } = req.body;
  
  // Simple validation
  if (!name || !email) {
    return res.status(400).json({
      success: false,
      message: 'Name and email are required'
    });
  }
  
  const newUser = {
    id: users.length + 1,
    name,
    email
  };
  
  users.push(newUser);
  
  res.status(201).json({
    success: true,
    message: 'User created successfully',
    data: newUser
  });
});
// GET all posts
app.get('/posts', (req, res) => {
  // Join posts with user data
  const postsWithUsers = posts.map(post => {
    const user = users.find(u => u.id === post.userId);
    return {
      ...post,
      author: user ? user.name : 'Unknown'
    };
  });
  
  res.json({
    success: true,
    data: postsWithUsers
  });
});
// GET post by ID
app.get('/posts/:id', (req, res) => {
  const id = parseInt(req.params.id);
  const post = posts.find(p => p.id === id);
  
  if (!post) {
    return res.status(404).json({
      success: false,
      message: 'Post not found'
    });
  }
  
  // Add author information
  const user = users.find(u => u.id === post.userId);
  const postWithAuthor = {
    ...post,
    author: user ? user.name : 'Unknown'
  };
  
  res.json({
    success: true,
    data: postWithAuthor
  });
});
// Error handling middleware
app.use((req, res) => {
  res.status(404).json({
    success: false,
    message: 'Endpoint not found'
  });
});
// Start server
app.listen(PORT, () => {
  console.log(`Server running on http://localhost:${PORT}`);
});

const express = require('express');
const router = express.Router();
let users = [
  { id: 1, name: 'John Doe', email: 'john@example.com' },
  { id: 2, name: 'Jane Smith', email: 'jane@example.com' }
];
// GET all users
router.get('/', (req, res) => {
  res.json(users);
});
// GET user by ID
router.get('/:id', (req, res) => {
  const user = users.find(u => u.id === parseInt(req.params.id));
  if (!user) return res.status(404).json({ error: 'User not found' });
  res.json(user);
});
// POST create user
router.post('/', (req, res) => {
  const newUser = {
    id: users.length + 1,
    ...req.body
  };
  users.push(newUser);
  res.status(201).json(newUser);
});
module.exports = router;

const express = require('express');
const app = express();
app.use(express.json());
// Import routes
const userRoutes = require('./routes/users');
// Use routes
app.use('/users', userRoutes);
app.get('/', (req, res) => {
  res.json({ message: 'API is working!' });
});
app.listen(3000, () => {
  console.log('Server started on port 3000');
});