AbortController lets you cancel fetch requests and other async operations mid-flight by calling abort(), which triggers an AbortError on the associated signal.
Reference
Built-in Objects
Core objects available in every JavaScript environment.
- AbortController
- Array
Creates arrays from iterables or array-likes with mapping support. Covers Array.isArray, Array.from, Array.of, and Array.fromAsync.
- ArrayBuffer
ArrayBuffer provides a fixed-length raw binary buffer. Learn to create, slice, transfer, and work with it using TypedArrays and DataView for binary data.
- BigInt
BigInt is a built-in object for arbitrary-precision integers beyond the Number.MAX_SAFE_INTEGER limit, with full arithmetic, comparison, and bitwise operations.
- console
The console object provides access to the browser or Node.js debugging console for logging, timing, grouping, and assertion-based debugging.
- DataView
DataView provides typed, low-level access to ArrayBuffer and SharedArrayBuffer with explicit endianness control for structured binary data parsing.
- Date
Represents dates and times using the JavaScript Date object for parsing date strings, manipulating timestamps, and formatting output across time zones.
- Error
The Error object represents runtime errors and is the base constructor for all JavaScript error types including TypeError, RangeError, and SyntaxError.
- FinalizationRegistry
FinalizationRegistry registers cleanup callbacks that fire when objects are garbage-collected. Part of ES2021, supported in modern browsers and Node.js.
- Intl
The Intl namespace provides language-sensitive formatting for numbers, dates, collators, and lists in JavaScript. Reference for all Intl constructors.
- Object
The Object constructor powers JavaScript's prototype system with static methods like Object.create() for inheritance and Object.assign() for merging properties.
- Reflect.apply()
Reflect.apply() invokes a target function with a given this value and arguments, providing the reflective equivalent of Function.prototype.apply().
- Reflect.construct()
Reflect.construct() invokes a target constructor with array-like arguments and an optional new.target, the reflective equivalent of the new operator.
- Reflect.defineProperty()
Reflect.defineProperty() installs a property descriptor on an object and returns a boolean for success or failure, rather than throwing.
- Reflect.deleteProperty()
Reflect.deleteProperty() removes a property from an object and returns a boolean indicating success — the functional form of the delete operator.
- RegExp
The JavaScript RegExp object for pattern matching — covers creation, flags, character classes, methods, and practical examples for text search and manipulation.
- Symbol
Create unique property keys with JavaScript Symbol primitives, including well-known symbols for customizing iteration, type conversion, and instanceof behavior.
- TextDecoder
TextDecoder converts raw byte buffers into JavaScript strings via the Encoding API. Supports UTF-8, streaming decode, and strict fatal mode for invalid input.
- TextEncoder
The TextEncoder API converts JavaScript strings into UTF-8 encoded byte sequences for binary storage, network transmission, and streaming text processing.
- TypedArray
TypedArray provides typed views over ArrayBuffer for binary data in JavaScript — essential for WebGL, canvas pixels, audio samples, and binary file handling.
- URLSearchParams
URLSearchParams reads, writes, and iterates query string parameters. Works with the URL interface for live manipulation and cross-platform query encoding.
- WeakRef
WeakRef holds a weak reference to an object, letting garbage collection reclaim memory when no strong references remain. Part of ES2021.