expressjsHow can I use Express.js to create efficient code patterns?

Express.js is a web application framework for Node.js that helps to create efficient code patterns. It provides a robust set of features for web and mobile applications, allowing developers to create applications quickly and efficiently.

Below is an example of an Express.js code pattern that uses the middleware pattern to create a simple web server:

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

// Use the middleware pattern
app.use((req, res, next) => {
  console.log('Request URL:', req.originalUrl);
  next();
}, (req, res, next) => {
  console.log('Request Type:', req.method);
  next();
});

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

app.listen(3000, () => {
  console.log('App listening on port 3000!');
});

Output example

Request URL: /
Request Type: GET
App listening on port 3000!

This code pattern consists of the following parts:

1. Requiring the Express.js module: This is done by using the require() function to import the Express.js module into the application.
2. Creating an Express.js application instance: This is done by using the express() function to create an Express.js application instance.
3. Using the middleware pattern: This is done by using the app.use() function to register middleware functions that will be executed on each request.
4. Handling a GET request: This is done by using the app.get() function to register a callback function that will be executed when a GET request is made to the application.
5. Listening for requests: This is done by using the app.listen() function to start the web server and listen for requests.

For more information about Express.js and how to create efficient code patterns, please refer to the following links:

• Express.js Documentation
• Express.js Middleware
• Express.js Routing

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