express.md

Adavantages of expresss

• It simplifies web development and middleware support • Middleware support • Flexible routing system • Template engine integretion

Create an http server in node.js

const express = require('express')
const app = express()
app.use(express.json())

const PORT = 3000
app.listen(PORT,()=> {
 console.log(`${PORT} listening`) }

Hello world in nodejs

const express = require('express')
const app = express()
app.use(express.json())

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

const PORT = 3000
app.listen(PORT,()=> {
 console.log(`${PORT} listening`) }

Middleware

HTTP Request -> middleware 1 (request logging)-> middleware 2(authentication) -> middleware3(CORS)

How do you implement middlware in express.js?

  const express = require("express")
  const app = express()
  const myMiddleware = (req,res,next) => {
     res.send("Interview ready")
     next()
  }
  app.use(myMiddleware)

app.use() is used for globally and for all methods

request pipeline

HTTP Request -> middleware 1 (request logging)-> middleware 2(authentication) -> middleware3(CORS)