Express.js

Express.js is..

A free and open-source web application framework for Node.js.It is used for designing and building web applications quickly and easily.Web applications are applications that can be run through a web browser. Because Express.js simply requires javascript, programmers and developers may quickly and easily create web apps and APIs.Because Express.js is a Node.js framework, the majority of the code is already developed and ready for programmers to use.
Express.js allows you to create single-page, multi-page, and hybrid online apps.
Express.js is a lightweight server-side framework that assists in the organization of web applications into a more structured MVC architecture.

Why use Express.js?

Express.js supports JavaScript, a widely used, easy-to-learn language that is also extensively supported. If you’re already familiar with JavaScript, programming with Express.js will be a breeze.

Express.js makes it simple to create various types of web apps in a short amount of time. For client requests, Express.js provides a simple routing system. It also includes middleware that is in charge of making decisions in order to offer the correct responses to the client’s requests.

To create a routing component without Express.js, you must write your own code, which is a time-consuming and laborious operation. Express.js provides programmers with simplicity, flexibility, efficiency, minimalism, and scalability. Because it is a Node.js framework, it also offers the benefit of high performance.

With the help of the Event Loop in Node.js, all of the executions are carried out very quickly, avoiding any inefficiency. The most popular characteristics liked by web application developers are the tremendous performance of Node.js and the ease of scripting with Express.js. Because Express.js is written in Javascript, it may be used to create webpages, web applications, and even mobile apps.

Features of Express.js

• Middleware

The database, client requests, and other middlewares are all accessible through middleware.
It’s mostly in charge of organizing Express.js’ main functions.

• Routing

ExpressJS has a sophisticated routing system that uses URLs to maintain the state of a webpage.

• Templating

ExpressJS has templating engines that enable developers to create dynamic content on web pages by creating HTML templates on the server.

• Faster server side development

Many standard Node.js functionalities are available as functions in Express.js, which can be called from anywhere in the program. This saves time by removing the need to code for several hours.

• Debugging

Debugging is essential for the creation of effective web apps. ExpressJS makes debugging simple by including a debugging feature that may determine the particular area of the web application that is causing problems.

Installing and using Express

First, Use this command to create a package.json file for your application.

npm init

Now install Express in the directory and save it in the dependencies list.

npm install express --save

or

npm i express --save

Let’s use our newly installed Express framework and create a simple “Hello World” in app.js file.

const express = require('express');
const app = express();
cont PORT = 5000;
app.get('/', (req,res) => {
   res.send('Hello World!');
})
app.listen(PORT, () => {
 console.log(`server running on PORT ${PORT}`);
})

Run the app with the following command:

node app.js

Express js Basic Routing

Respond with Hello World! on the homepage:

app.get('/', function (req, res) {
  res.send('Hello World!')
})

Respond to POST request on the root route (/), the application’s home page:

app.post('/', function (req, res) {
  res.send('Got a POST request')
})

Respond to a PUT request to the /user route:

app.put('/user', function (req, res) {
  res.send('Got a PUT request at /user')
})

Respond to a DELETE request to the /user route:

app.delete('/user', function (req, res) {
  res.send('Got a DELETE request at /user')
})

Thank you.. !