Express Js :
Express.js is a popular web application framework for Node.js, designed for building web applications and APIs. It provides a minimalist and flexible set of features, allowing developers to quickly build robust and scalable web applications.
Pros
- Widely used: as you can see in this visual report there is still a good demand for job opportunities.
- Community and a lot of integrated tools: Since so many people are using ExpressJS you can find a lot of libraries solving the problems around ExpressJS.
- Simplicity: It takes a few minutes for a junior developer to get how to create a simple app with ExpressJS.
- Middleware: Nowadays the idea of middleware is implemented in most frameworks which is a good thing and it solves some reoccurring problems in applications.
Cons
- Performance: You can see in the benchmark that it is not the fastest HTTP library in Nodejs and compared to something like Fastify it is slow!
- Security: It does not offer some of the security checks needed capabilities or validations by default so you need to implement them yourself or use a third-party library.
Here’s a brief overview of Express.js:
Introduction:
- Node.js: Express.js is built on top of Node.js, leveraging its asynchronous, event-driven architecture for high-performance web applications.
- Middleware: Express.js uses middleware functions to handle various HTTP requests and responses. Middleware functions are functions that have access to the request object (req), the response object (res), and the next function in the application’s request-response cycle.
- Routing: It provides a simple yet powerful routing mechanism to define routes based on HTTP methods and URL patterns.
- Template Engines: Express.js allows integration with various template engines like EJS, Pug, Handlebars, etc., for generating dynamic HTML content.
- Modularity: Express.js encourages a modular approach to building applications, allowing developers to organize their code into smaller, reusable components.
- Community: It has a large and active community with a rich ecosystem of middleware and plugins available for extending its functionality.
Syntax:
Express.js syntax is straightforward and intuitive. Here’s a basic example :
Javascript :
const express = require(‘express’);
const app = express();
app.get(‘/’, (req, res) => {
res.send(‘Hello World!’);
});
app.listen(3000, () => {
console.log(‘Server is running on port 3000’);
});
This example creates a simple Express.js application that listens for HTTP requests on port 3000 and responds with “Hello World!” when the root URL is accessed via a GET request.
Express.js offers much more functionality beyond this basic example, including routing, middleware usage, template rendering, error handling, and much more.
Where used :
Web Applications: Express.js is commonly used to build web applications of all sizes, from small projects to large-scale enterprise applications.
APIs: It’s often used to create RESTful APIs for client-server communication in web and mobile applications.
Single Page Applications (SPAs): Express.js can serve as a backend for SPAs built with frameworks like React, Angular, or Vue.js.
Microservices: Due to its lightweight and modular nature, Express.js is well-suited for building microservices architecture.
Real-time Applications: It can be used in conjunction with WebSocket libraries like Socket.io to build real-time web applications.
How to Use:
To use Express.js in a Node.js application, you first need to install it using npm (Node Package Manager):
npm install express
Then, in your Node.js application, you import Express and create an instance of the Express application :
const express = require(‘express’);
const app = express();
You can define routes to handle different HTTP methods and URL patterns using the app.METHOD() functions, where METHOD is the HTTP method (e.g., GET, POST, PUT, DELETE).
app.get(‘/’, (req, res) => {
res.send(‘Hello World!’);
});
Express.js middleware functions are also crucial for handling tasks like parsing request bodies, authentication, logging, etc.
app.use(express.json()); // Middleware for parsing JSON bodies
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