Node.js - Built-in Modules

A module in Node.js is a collection of independent and reusable code that can be imported into any Node.js application. The Node.js runtime software comes with the V8 JavaScript engine, bundled with a number of core modules, that perform important server-side tasks, such as managing event loop, perform file IO and operating system-specific functions etc.

Example

The following code snippet returns a list of all the built-in modules −

 const builtinModules = require('repl')._builtinLibs;
 console.log(builtinModules);

Output

[
  'assert',             'assert/strict',       'async_hooks',
  'buffer',             'child_process',       'cluster',
  'console',            'constants',           'crypto',
  'dgram',              'diagnostics_channel', 'dns',
  'dns/promises',       'domain',              'events',
  'fs',                 'fs/promises',         'http',
  'http2',              'https',               'inspector',
  'inspector/promises', 'module',              'net',
  'os',                 'path',                'path/posix',
  'path/win32',         'perf_hooks',          'process',
  'punycode',           'querystring',         'readline',
  'readline/promises',  'repl',                'stream',
  'stream/consumers',   'stream/promises',     'stream/web',
  'string_decoder',     'sys',                 'timers',
  'timers/promises',    'tls',                 'trace_events',
  'tty',                'url',                 'util',
  'util/types',         'v8',                  'vm',
  'wasi',               'worker_threads',      'zlib'
]

Node.js has many core modules that provide essential functionalities for building applications. Here's a list of some of the most important core modules −

Sr.No	Core Modules & Description
1	http Provides an interface for creating HTTP servers and making HTTP requests.
2	fs Provides functions for working with files and directories.
3	path Provides functions for working with file paths.
4	url Provides functions for parsing and building URLs.
5	util Provides utility functions for working with data and strings.
6	crypto Provides functions for cryptography and secure hashing.
7	process Provides information about the current Node.js process and allows you to interact with the operating system.
8	net Provides low-level networking functionality.
9	stream Provides a basic framework for working with streams of data.
10	events Provides an event emitter class for custom event handling.
11	console Provides functions for writing to the console.
12	readline Provides functions for reading line-by-line from a stream.

Select a module to see a list of all the methods related to that module −