What is Express.js and how do I get started with it?

What is Express.js and how do I get started with it?

Express.js is a web application framework for Node.js, designed for building web applications and APIs. To get started, you need to have Node.js installed. Then, you can create a new project and install Express using npm.

Can you show me a simple example of an Express.js application?

Sure! Here's a basic example:

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

app.get('/', (req, res) => {
  res.send('Hello World!');
});

app.listen(3000, () => {
  console.log('Server is running on http://localhost:3000');
});

This code sets up a simple server that responds with 'Hello World!' when you access the root URL.

What are some common middleware used in Express.js?

Some common middleware in Express.js include:

1. body-parser for parsing request bodies.
2. morgan for logging requests.
3. cors for enabling Cross-Origin Resource Sharing.

How do I handle errors in an Express.js application?

You can handle errors in Express.js by defining an error-handling middleware. Here's an example:

app.use((err, req, res, next) => {
  console.error(err.stack);
  res.status(500).send('Something broke!');
});