JavaScript Global Objects

29 in total

Global objects are JavaScript's built-in toolkit — Array, String, Object, Math, JSON, Promise and more. Each one bundles related methods and properties you can use anywhere without importing a thing. Here are all 29, each with its key members and live examples.

Name	Description
AbortController	Lets you cancel async operations like fetch requests, event listeners and timers via a signal.
Array	The built-in object for ordered lists of values, with dozens of methods for transforming them.
BigInt	A primitive type for integers larger than Number can safely represent.
Boolean	The true/false type, plus the rules of truthy and falsy values that drive conditions.
Date	The built-in object for working with dates and times — creating, reading and formatting them.
Error	The object that represents a runtime error, carrying a message and a stack trace.
FormData	Collects form field values into an object you can read or send, including file uploads.
globalThis	A standard reference to the global object that works in browsers, Node and workers alike.
IntersectionObserver	Efficiently watches when elements enter or leave the viewport — for lazy loading and scroll effects.
Intl.DateTimeFormat	Formats dates and times for a locale, with control over which parts to show.
Intl.NumberFormat	Formats numbers, currency and percentages for a locale, with separators and symbols.
JSON	A built-in namespace for converting between JavaScript values and JSON text with stringify and parse.
localStorage	Browser storage that keeps string key-value data on the user's device, even after the page closes.
Map	A key-value collection that allows any type of key and remembers insertion order.
Math	A built-in namespace of mathematical constants and functions like random, round, floor and max.
MutationObserver	Watches an element for DOM changes — added or removed nodes, attribute and text changes.
Number	The built-in for numeric values, with helpers for parsing, formatting and validating numbers.
Object	The built-in for key-value collections, plus static helpers like Object.keys and Object.assign.
Promise	An object representing the eventual result of an asynchronous operation — pending, fulfilled or rejected.
Proxy	Wraps an object to intercept and customize operations like reading, writing and deleting properties.
Reflect	A built-in object with methods that perform the default operations on objects, designed to pair with Proxy.
RegExp	A pattern for matching text — used to search, validate, extract and replace strings.
sessionStorage	Browser storage that keeps string key-value data only for the current tab session.
Set	A collection of unique values — duplicates are automatically ignored.
String	The built-in object for text, with methods for searching, slicing and transforming strings.
Symbol	A primitive that creates a unique, collision-proof identifier, often used as an object key.
URLSearchParams	A helper for reading and building URL query strings without manual string parsing.
WeakMap	A Map whose keys must be objects and are held weakly, so they can be garbage collected.
WeakSet	A Set whose values must be objects and are held weakly, so they can be garbage collected.

References