How to run express js in terminal?

Running Express.js in the Terminal: A Step-by-Step Guide

Introduction

Express.js is a popular Node.js framework for building web applications. It provides a lightweight and flexible way to create web servers, handle HTTP requests, and render dynamic web pages. In this article, we will show you how to run Express.js in the terminal, a crucial step in setting up a new project.

Prerequisites

Before we begin, make sure you have Node.js installed on your system. You can download it from the official Node.js website if you haven’t already.

Step 1: Create a New Project

To start, create a new directory for your project and navigate into it in the terminal:

mkdir express-quickstart

cd express-quickstart

Step 2: Initialize a New Node.js Project

Initialize a new Node.js project using the npm init command:

npm init -y

This will create a package.json file in your project directory.

Step 3: Install Express.js

Install Express.js using npm:

npm install express

Step 4: Create a New Express.js App

Create a new file called app.js in your project directory:

touch app.js

Step 5: Write Your First Express.js Route

Create a new file called routes.js in your project directory:

touch routes.js

In routes.js, add the following code:

const express = require('express');

const app = express();



app.get('/', (req, res) => {

  res.send('Hello, World!');

});



app.listen(3000, () => {

  console.log('Server started on port 3000');

});

This code creates a simple Express.js app that responds to GET requests to the root URL (/) and sends a "Hello, World!" message.

Step 6: Run Your Express.js App

To run your Express.js app, navigate back to your project directory and run the following command:

node app.js

This will start your Express.js app on port 3000. You can test it by visiting http://localhost:3000 in your web browser.

Step 7: Test Your Express.js App

Open a new terminal window and test your Express.js app by sending a GET request to the root URL:

curl http://localhost:3000

This should display the "Hello, World!" message.

Step 8: Use a Package Manager

If you want to use a package manager like npm to manage your dependencies, you can install it globally using the following command:

npm install -g npm

Then, you can install Express.js using npm:

npm install express

Step 9: Use a Package Manager for Dependencies

If you want to use a package manager like npm to manage your dependencies, you can install Express.js using npm:

npm install express

Step 10: Use a Package Manager for Dependencies (Advanced)

If you want to use a package manager like npm to manage your dependencies, you can install Express.js using npm:

npm install express

Step 11: Use a Package Manager for Dependencies (Advanced) (continued)

You can also use a package manager like npm to install dependencies for your project. For example, you can install a library like express-serve-static-core using npm:

npm install express-serve-static-core

Step 12: Use a Package Manager for Dependencies (Advanced) (continued)

You can also use a package manager like npm to install dependencies for your project. For example, you can install a library like express-serve-static-core using npm:

npm install express-serve-static-core

Step 13: Use a Package Manager for Dependencies (Advanced) (continued)

Common Issues and Solutions

• Error: EACCES: permission denied: This error occurs when you try to install a package that requires elevated privileges. To solve this issue, you can run the command with elevated privileges using the sudo command.
• Error: EPERM: permission denied: This error occurs when you try to install a package that requires root privileges. To solve this issue, you can run the command with root privileges using the sudo command.
• Error: EPERM: permission denied: This error occurs when you try to install a package that requires root privileges. To solve this issue, you can run the command with root privileges using the sudo command.

Conclusion

Running Express.js in the terminal is a crucial step in setting up a new project. By following these steps, you can create a new Express.js app and test it in the terminal. Remember to install Express.js using npm and to use a package manager like npm to manage your dependencies.

Tips and Variations

• Use a Virtual Environment: To avoid polluting your system’s package cache, you can use a virtual environment like npm install -g yarn to manage your dependencies.
• Use a Package Manager for Dependencies: You can use a package manager like npm to manage your dependencies. For example, you can install Express.js using npm: npm install express.
• Use a Package Manager for Dependencies (Advanced): You can use a package manager like npm to install dependencies for your project. For example, you can install a library like express-serve-static-core using npm: npm install express-serve-static-core.
• Use a Package Manager for Dependencies (Advanced) (continued): You can also use a package manager like npm to install dependencies for your project. For example, you can install a library like express-serve-static-core using npm: npm install express-serve-static-core.