Getting Started with Express.js

A minimalist, powerful web framework for Node.js

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What is Express.js?

Express.js is a minimalist web framework for Node.js, designed for building web applications and APIs quickly and easily. In this article, we’ll explore the basics of Express.js and see how to create a simplest web application example using this powerful framework.

Beside being a flexible and lightweight framework Express.js provides a robust set of features for web and mobile applications. It simplifies the process of creating server-side logic and handling HTTP requests and responses. Express.js follows the middleware pattern, allowing developers to modularize their code and add functionality in a structured manner.

Installing Express.js:

Before we dive into building our application, let’s install Express.js. Assuming you have Node.js installed, you can install Express.js using npm, the Node.js package manager:

npm install express

Creating a Simple Express Application:

Now that we have Express.js installed, let’s create a simple web application. Create a new file called app.js and add the following code:

• Here, we import the Express.js module using the require function provided by Node.js. The require('express') statement imports the Express.js library, allowing us to use its features to create web servers and define routes.
• After importing Express.js, we create an instance of the Express application by calling the express() function. This app object represents our web application and provides methods for defining routes, middleware, and other settings.
• Here, we define a route for the root URL (/) using the app.get() method. This method takes two parameters: the route path ('/' in this case) and a callback function that handles the request and response. When a GET request is made to the root URL, the callback function sends the response 'Hello, Express!' using the res.send() method.
• Finally, we start the server and make it listen for incoming requests on a specific port (in this case, port 3000) using the app.listen() method. When the server starts listening, the callback function is executed, and a message is logged to the console indicating that the server is running.

Running the Application:

node app.js

As you run this code, it creates a simple web server using Express.js that responds with “Hello, Express!” when you visit the root URL (http://localhost:3000/) in your web browser.

Adding Middleware:

Express.js allows us to use middleware to enhance the functionality of our application. Middleware functions have access to the request and response objects and can modify them as needed. Let’s add a middleware function to log the timestamp of each incoming request:

Now, each time a request is made to our server, the timestamp along with the HTTP method and URL will be logged to the console.

Conclusion:

Express.js offers a wide range of features, including routing, middleware, template engines, and much more. Whether you’re building a small-scale web application or a large-scale API, Express.js provides the tools you need to get the job done efficiently.

For more information and advanced topics, refer to the Express.js documentation.

What Next??

This introductory overview barely scratches the surface of what Express can accomplish. Understanding the real-world scenarios where Express excels is crucial. In the next article, we’ll delve into the intricacies of Express’s applications, accompanied by code snippets, to illustrate its functionality comprehensively.

Real-time use case examples