What is node.js and express.js?
Node.js is an open-source server-side platform built on Google Chrome's JavaScript engine. It allows developers to build scalable, high-performance applications using JavaScript on the server-side.
Express.js is a popular web framework for Node.js that simplifies the process of building web applications. It provides a robust set of features for building web applications and APIs, including routing, middleware, templating, and more.
Prerequisites
Before you begin, make sure you have Node.js installed on your system. You can download the latest version of Node.js from the official website: https://nodejs.org/
Step 1. Create a new Node.js project
Create a new directory for your project and navigate into it:
mkdir myapp
cd myapp
Initialize a new Node.js project using npm:
npm init -y
This command will create a package.json file in your project directory.
Step 2. Install Express.js
Install Express.js using npm:
npm install express
This will install the latest version of Express.js and its dependencies in your project directory.
Step 3. Create an Express.js app
Create a new file called app.js in your project directory and open it in your code editor.
Import the express module at the top of the file:
const express = require('express');
Create a new instance of the Express app:
const app = express();
Step 4. Define a route
Define a route for the homepage ('/') using the app.get() method:
app.get('/', (req, res) => {
res.send('Hello, World!');
});
This code defines a route for the homepage ('/') that sends the message "Hello, World!" when a request is made to it.
Step 5. Start the server
Start the server and listen on port 3000 using the app.listen() method:
app.listen(3000, () => {
console.log('Server is listening on port 3000');
});
This code starts the server and listens on port 3000. When the server starts, it logs a message to the console.
Step 6. Test the app
Run the app using the following command:
node app.js
This will start the server and make your app available at http://localhost:3000/.
Open your web browser and navigate to http://localhost:3000/. You should see the message "Hello, World!" displayed on the page.
You've created a simple Node.js and Express.js app! You can build on this app by adding more routes, middleware, and functionality as needed.