Category: React • Beginner
Published on 02 Mar 2026
Explanation
Create a Node.js project install the Express framework.
Code Example
npm init -y npm install express
Explanation
Import Express, create an app instance and enable JSON middleware to parse incoming request bodies.
Code Example
const express = require('express');
const app = express();
app.use(express.json());
Explanation
Create a sample in-memory array to store user data.
Code Example
let users = [
{ id: 1, name: 'Praveen' },
{ id: 2, name: 'Kumar' }
];
Explanation
GET API to retrieve all users.
Code Example
app.get('/users', (req, res) => {
res.json(users);
});
Explanation
GET API to retrieve a single user by ID. Returns 404 if not found.
Code Example
app.get('/users/:id', (req, res) => {
const user = users.find(
u => u.id == req.params.id
);
if (!user) return res.status(404).json(
{ message: 'User not found' }
);
res.json(user);
});
Explanation
POST API to create a new user. Returns 201 status code after successful creation.
Code Example
app.post('/users', (req, res) => {
const newUser = {
id: users.length + 1,
name: req.body.name
};
users.push(newUser);
res.status(201).json(newUser);
});
Explanation
PUT API to update a user by ID.
Code Example
app.put('/users/:id', (req, res) => {
const user = users.find(
u => u.id == req.params.id
);
if (!user) return res.status(404).json(
{ message: 'User not found' }
);
user.name = req.body.name;
res.json(user);
});
Explanation
DELETE API to remove a user by ID.
Code Example
app.delete('/users/:id', (req, res) => {
users = users.filter(
u => u.id != req.params.id
);
res.json({ message: 'User deleted' });
});
Explanation
Start the Express server on port 3000.
Code Example
app.listen(3000, () => {
console.log('Server running');
});