bur什么品牌 Node.js Tutorial

Node.js Tutorial ❮ Home Next ❯ What is Node.js?

Node.js is a free, open source tool that lets you run JaScript outside the web browser.

With Node.js, you can build fast and scalable applications like web servers, APIs, tools, and more.

Start learning Node.js now » 🏁

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What Can You Build With Node.js?

Node.js uses an event-driven, non-blocking model.

It can handle many connections at once without waiting for one to finish before starting another.

This makes it great for real-time apps and high-traffic websites.

Here are some examples of what you can build with Node.js:

Web servers and websites REST APIs Real-time apps (like chat) Command-line tools Working with files and databases IoT and hardware control How to Run Node.js Code

Se your code in a file, for example app.js, then run it in your terminal or command prompt with:

node app.js

This will start your Node.js program.

Learning by Examples

Our "Show Node.js" tool makes it easy to learn Node.js, it shows both the code and the result.

Example let http = require('http');

http.createServer(function (req, res) { res.writeHead(200, {'Content-Type': 'text/plain'}); res.end('Hello World!'); }).listen(8080);

Run example »

Click on the "Run example" button to see how it works.

Examples Running in the Command Line Interface

In this tutorial there will be some examples that are better explained by displaying the result in the command line interface.

When this happens, The "Show Node.js" tool will show the result in a black screen on the right:

Example console.log('This example is different!'); console.log('The result is displayed in the Command Line Interface'); Try it Yourself »

Click on the "Run example" button to see how it works.

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Node.js Built-in Modules

Node.js comes with many built-in modules to help you work with files, servers, paths, the operating system, and more.

You can use them by importing them with require().

Example: Using the OS Module const os = require('os'); console.log(os.platform()); Try it Yourself »

See the full list of built-in modules.

What is npm?

npm is the package manager for Node.js.

It helps you install and manage third-party packages (libraries) to add more features to your apps.

Example: Installing a Package npm install express

This command installs the popular Express web framework.

You can then use it in your code:

const express = require('express'); const app = express(); app.get('/', (req, res) => res.send('Hello World!')); app.listen(8080); Run example » Download Node.js

Download Node.js from the official Node.js web site: https://nodejs.org

Node.js Exercises

Many chapters in this tutorial end with an exercise where you can check your level of knowledge.