Standard Built-in Objects

JavaScript’s standard built-in objects provide the language’s global objects and functions. This area follows the ECMAScript specification, including ECMA-402 for internationalization, and MDN’s standard built-in objects index. Most built-in functionality lives on global objects, with methods such as Math.max(), JSON.parse(), and Promise.all().

Each entry here covers one object or global function, with its constructor or call form, a table of the methods developers reach for, and short examples you can run in a JavaScript console.

Topics covered include:

  • Fundamental objects: The foundations of objects and callable values (Object, Function, Boolean, Symbol, globalThis)
  • Numbers and text: Numeric, text, and formatting helpers (Number, Math, String, RegExp, Intl)
  • Dates and time: Date storage and time calculations (Date, Temporal)
  • Collections: Indexed and keyed containers, plus weak references (Array, Map, Set, WeakMap, WeakRef)
  • Iteration and async: Iterator operations and asynchronous results (Iterator, Promise)
  • Binary data: Raw memory and views over it (ArrayBuffer, DataView, Atomics, typed arrays)
  • Structured data and reflection: JSON conversion and object-operation hooks (JSON, Proxy, Reflect)
  • Errors: The error hierarchy and its subclasses (Error, TypeError)
  • Resource management: Helpers for deterministic cleanup (DisposableStack, AsyncDisposableStack)
  • ECMAScript global functions: Parsing, URI encoding, and evaluation (parseInt(), isNaN(), encodeURIComponent(), eval())

The lowercase primitive types (string, number, bigint) live in JavaScript Primitive Types, which covers literals, typeof, and coercion. Reserved words such as new, class, and await live in JavaScript Keywords. Concepts like promises, iterators, and prototypes as ideas live in the JavaScript Glossary. Host APIs such as console, setTimeout(), and fetch() live in Web APIs. This area picks up the language’s own objects and functions, with their methods.

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  • BigInt A global object that converts values to arbitrary-size integers, with asIntN() and asUintN() for fixed-width wrapping and toString() for any radix.
  • Boolean A global object that converts values to true or false and wraps booleans in objects, with toString() and valueOf() methods.
  • Function A global object that is the constructor of ordinary functions, with the call(), apply(), and bind() methods that all functions inherit.
  • globalThis A global property that refers to the global object, giving every JavaScript host one shared name for it.
  • Intl A global object that groups constructors for locale-aware formatting of numbers, dates, lists, and plurals, plus string comparison and text segmentation.
  • Math A global object that groups math constants and functions for rounding, powers, logarithms, trigonometry, and random numbers.
  • Number A global object that converts values to numbers, with constants, integer and NaN checks, and formatting methods like toFixed().
  • Object The only non-primitive type, a mutable collection of properties compared by reference, which also covers arrays, functions, dates, and class instances.
  • Promise A global object that represents the eventual result of an asynchronous operation, with static methods to create, combine, and race promises.
  • String A global object that converts values to strings and wraps them in objects, with methods to search, slice, pad, and replace text.
  • Symbol A global object that creates unique symbol values and holds well-known symbols, such as Symbol.iterator, that customize built-in behavior.
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