Express.js Framework

Express is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications.

Installation

bash

npm init -y
npm install express

Basic Server

javascript

const express = require('express')
const app = express()

app.get('/', (req, res) => {
  res.send('Hello Express!')
})

app.listen(3000, () => {
  console.log('Server is running on port 3000')
})

Routing

javascript

app.get('/users', (req, res) => {
  res.json([{ id: 1, name: 'John' }])
})

app.post('/users', (req, res) => {
  // Create user
})

app.put('/users/:id', (req, res) => {
  const { id } = req.params
  // Update user
})

app.delete('/users/:id', (req, res) => {
  // Delete user
})

Middleware

javascript

// Built-in middleware
app.use(express.json())
app.use(express.static('public'))

// Custom middleware
app.use((req, res, next) => {
  console.log(`${req.method} ${req.path}`)
  next()
})