#JavaScript Modules

Pure JavaScript modules (lib/*.js) providing polyfills for standard APIs, wrappers around native modules, and prototype extensions.

#Complete List

#Core & Language Extensions

• util — Central utility library
• reflect — Reflection and value serialization
• iterator — Base iterator class
• asyncIterator — Async iterator base class
• arrayLike — Array-like base class

#Prototype Extensions

• extendArray — Array prototype extensions
• extendArrayBuffer — ArrayBuffer prototype extensions
• extendObject — Object prototype extensions
• extendMap — Map prototype extensions
• extendSet — Set prototype extensions
• extendMath — Math object extensions
• extendFunction — Function prototype extensions
• extendAsyncFunction — AsyncFunction prototype extensions
• extendGenerator — Generator prototype extensions
• extendAsyncGenerator — AsyncGenerator prototype extensions

#Runtime / Node.js Compatible

• assert — Node.js assert module
• console — WHATWG Console API
• process — Node.js process object
• events — Node.js EventEmitter
• abort — AbortController/AbortSignal
• timers — HTML5 Timers API (setTimeout, setInterval, etc.)
• perf_hooks — Performance hooks
• module — Module utilities
• require — CommonJS require
• stack — Stack utilities

#I/O & Filesystem

• fs — Node.js fs module (wraps native modules)
• fsPromises — Promise-based fs API
• io — I/O utilities
• streams — Stream utilities
• vfs — Virtual filesystem
• inotify — inotify wrapper
• tty — TTY utilities
• terminal — Terminal utilities
• socklen_t — Socket length type

#Parsing, DOM & Selectors

• dom — W3C DOM API (wraps native modules)
• xpath — XPath implementation
• parser — Parser combinator framework
• grammar — Grammar utilities
• parsel — CSS selector parser
• css-selectors — CSS selector engine
• css3-selectors — CSS3 selector engine
• url — WHATWG URL API (polyfill)

#Databases

• db — Database utilities
• database (lib/database.js) — Database abstraction (undocumented)

#Tooling

• repl — REPL implementation
• testharness — W3C test harness
• testharnessreport — Test harness reporting

#Utilities

• buffer — Buffer utilities
• readline — Readline utilities
• describe-class (lib/describe-class.js) — Class description utilities (undocumented)
• dbi (lib/dbi.js) — Database interface (undocumented)

#Module Classification

#Polyfills (Standalone JS)

Pure JavaScript implementations of standard APIs with no native dependencies:

• WHATWG/W3C/HTML5: events, url, timers, abort, console
• Node.js: assert, fs (partial), process (partial)
• Utilities: iterator, asyncIterator, arrayLike

#Wrappers (Wrap Native Modules)

JavaScript code that wraps native modules to provide higher-level APIs:

• fs — Wraps misc, mmap, syscallerror
• fsPromises — Wraps fs
• dom — Wraps fs, util, timers, css3-selectors, deep, pointer, tree-walker, xml, url
• console — Wraps os, util, inspect, std
• process — Wraps os, path, util, misc, std
• assert — Wraps util
• util — Wraps misc, timers

#Prototype Extensions

Extend built-in JavaScript prototypes (Array, Object, Map, etc.):

• extendArray, extendArrayBuffer, extendObject, extendMap, extendSet, extendMath
• extendFunction, extendAsyncFunction, extendGenerator, extendAsyncGenerator

#Statistics

• Total JS modules: 60+
• Polyfills: 25 (standalone JS implementations)
• Wrappers: 32 (wrap native modules)
• Extensions: 10 (prototype extensions)

#Standards Compliance

• WHATWG/W3C/HTML5: events, url, timers, abort, console, dom
• Node.js: assert, fs, fsPromises, process, events, util
• Custom: Many utility modules (see api-compatibility.md)