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Node.js Built-In Modules

Node.js provides a rich set of built-in modules that offer core functionalities to build applications without needing external libraries. These modules are directly available without installation, making development faster and more efficient.

 

Key Features of Built-In Modules

  1. Predefined functionality like file handling, networking, and more are readily available.
  2. Built-in modules are part of the Node.js runtime and need no installation.
  3. Optimized for speed and reliability, ensuring high performance.
  4. Require minimal setup and offer intuitive APIs for developers.

 

Commonly Used Built-In Modules

Here are some popular built-in modules in Node.js:

  1. fs (File System): Handles file operations such as reading, writing, and deleting files.
  2. http: Enables creating HTTP servers and handling requests/responses.
  3. path: Simplifies working with file paths.
  4. os: Offers system-related utilities like CPU and memory information.
  5. events: Manages events using the EventEmitter class.
  6. util: Includes utility functions like formatting and debugging.

 

Example Code

Using the fs Module

const fs = require('fs');  

// Writing to a file  
fs.writeFileSync('example.txt', 'Hello, World!');  
console.log('File written successfully.');  

// Reading from a file  
const data = fs.readFileSync('example.txt', 'utf8');  
console.log('File content:', data);

This example demonstrates writing to and reading from a file using the fs module.

Using the http Module

const http = require('http');  

// Create an HTTP server  
const server = http.createServer((req, res) => {  
  res.statusCode = 200;  
  res.setHeader('Content-Type', 'text/plain');  
  res.end('Hello, World!\n');  
});  

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

This example shows how to create a simple HTTP server that responds with "Hello, World!".

Using the path Module

const path = require('path');  

// Join paths  
const fullPath = path.join('/users', 'john', 'docs', 'file.txt');  
console.log('Full Path:', fullPath);  

// Get file extension  
const ext = path.extname('file.txt');  
console.log('File Extension:', ext);

This example demonstrates working with file paths using the path module.

Using the os Module

const os = require('os');  

console.log('Operating System:', os.type());  
console.log('Total Memory:', os.totalmem());  
console.log('Free Memory:', os.freemem());  
console.log('CPU Info:', os.cpus());

This example retrieves information about the operating system and hardware using the os module.

 

Summary

Node.js built-in modules provide essential functionalities for building applications without requiring additional libraries. Popular modules like fs, http, path, os, and events simplify operations ranging from file handling to creating servers. These modules are pre-installed, optimized, and ready to use, making development in Node.js efficient and powerful.

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