Setting up an Express.js Application

Express.js is a powerful JavaScript framework that allows developers to build robust and scalable web applications. In this article, we will walk through the process of setting up an Express.js application.

Prerequisites

Before getting started, make sure you have Node.js installed on your system. You can easily download and install the latest version of Node.js from the official website (https://nodejs.org).

Initializing the Project

To start a new Express.js project, we first need to create a new directory for our application. Open your terminal or command prompt, navigate to your desired directory, and run the following command:

mkdir my-express-app

Then, navigate into the project directory by running:

cd my-express-app

Next, we need to initialize our project with npm (Node Package Manager). Run the following command:

npm init -y

This command creates a package.json file which will track our project dependencies and other configurations.

Installing Express.js

With our project initialized, we can now install Express.js as a dependency. In the terminal, run the following command:

npm install express

This command installs the latest version of Express.js and saves it as a dependency in the package.json file.

Creating the Server

Now that we have Express.js installed, let's create our server. In the project directory, create a new file called app.js (or any other name of your choice) using your favorite code editor.

In app.js, we will import the Express.js module and initialize our server. Add the following code:

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

const port = 3000;

app.listen(port, () => {
  console.log(`Server started on port ${port}`);
});

This code sets up a basic Express.js server that listens on port 3000. When the server starts, it will log a message to the console.

Starting the Server

To start our server, go back to your terminal or command prompt and run the following command:

node app.js

You should see the following message in your console:

Server started on port 3000

Congratulations! You have successfully set up a basic Express.js application.

Testing the Server

To make sure everything is working as expected, open your browser and navigate to http://localhost:3000. You should see a "Cannot GET /" message. This is expected as we haven't defined any routes yet.

Conclusion

In this article, we learned how to set up an Express.js application from scratch. We initialized a new project, installed Express.js as a dependency, created a basic server, and started it to test our setup. Now you are ready to start building your own powerful web applications using the Express.js framework. Happy coding!