What is Express.js? Introduction to Basic Concepts

Express.js is a minimalist web application framework developed on Node.js. This framework, which allows you to create web applications and APIs quickly and easily, offers flexible features that provide developers with flexibility and fast development opportunities. Especially when designing RESTful APIs, thanks to the conveniences provided by Express.js, projects can be brought to life rapidly.

Basic Features of Express.js

Express.js stands out with many basic features. Among the most prominent of these are middleware usage, routing, and error management. Middleware plays an important role in handling incoming requests; it makes processing requests, preparing responses, and error catching easier. This also contributes to making the code more modular and readable.

Using Middleware

Middleware are functions used to add various functionalities in your Express.js application. Below is a simple example of middleware:

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

app.use((req, res, next) => {
    console.log('A new request has arrived:', req.method, req.url);
    next(); // Pass control to the next middleware or route.
});

app.get('/', (req, res) => {
    res.send('Welcome to the Homepage!');
});

app.listen(3000, () => {
    console.log('Server is running on port 3000.');
});

Routing

Express.js makes it easy to manage URL routing. For example, you can use routing to respond to requests coming to a specific URL with different functions:

app.get('/about', (req, res) => {
    res.send('About Page');
});

app.post('/contact', (req, res) => {
    res.send('Contact form submitted.');
});

Conclusion

In conclusion, as a powerful part of the Node.js ecosystem, Express.js offers developers the ability to develop fast and effective web applications. With the flexibility and modular structure to suit project needs, Express.js is an indispensable tool for developers of all levels. For those who want to accelerate the application development process and write cleaner code, Express.js is an excellent choice.