Blog
Docs
Playground
Changelog
Theme
v4
v3 (default)
v3
v4 (alpha)
Usage
Supported engines and compatibility data
TypeScript type definitions
Features
ECMAScript
ECMAScript: Object
ECMAScript: Function
ECMAScript: Error
ECMAScript: Array
ECMAScript: Iterator
ECMAScript: String and RegExp
ECMAScript: Number
ECMAScript: Math
ECMAScript: Date
ECMAScript: Promise
ECMAScript: Symbol
ECMAScript: Collections
ECMAScript: Explicit resource management
ECMAScript: Typed arrays
ECMAScript: Reflect
ECMAScript: JSON
ECMAScript: globalThis
ECMAScript proposals
Finished proposals
globalThis
Relative indexing method
Array.prototype.includes
Array.prototype.{ flat, flatMap }
Array find from last
Change Array by copy
Array grouping
Array.fromAsync
ArrayBuffer.prototype.transfer and friends
Uint8Array to/from base64 and hex
Error cause
Error.isError
Explicit resource management
Float16
Iterator helpers
Iterator sequencing
Iterator chunking
Iterator includes
Iterator join
Joint iteration
Object.values / Object.entries
Object.fromEntries
Object.getOwnPropertyDescriptors
Accessible Object.prototype.hasOwnProperty
String padding
String.prototype.matchAll
String.prototype.replaceAll
String.prototype.{ trimStart, trimEnd }
RegExp s (dotAll) flag
RegExp named capture groups
RegExp escaping
Promise.allSettled
Promise.any
Promise.prototype.finally
Promise.try
Promise.withResolvers
Asynchronous iteration
Symbol.prototype.description
JSON.parse source text access
Well-formed JSON.stringify
Well-formed Unicode strings
New Set methods
Map upsert
Math.sumPrecise
Stage 3 proposals
Await dictionary
Stage 2.7 proposals
Decorator metadata
Stage 2 proposals
Async iterator helpers
Iterator.range
Number.prototype.clamp
String.dedent
Symbol predicates
Extractors
Object.keysLength
Stage 1 proposals
DataView get/set Uint8Clamped methods
String.cooked
Pattern matching
Stage 0 proposals
Demethodize function
Web standards
self
structuredClone
Base64 utility methods
setImmediate
queueMicrotask
URL and URLSearchParams
DOMException
Iterable DOM collections
Iteration helpers
Missing polyfills
Contributing
Security policy
globalThis
Specification
Proposal repo
Built-ins signatures
let globalThis: GlobalThisValue;
Entry points
core-js/proposals/global-this
Built-ins signatures
Entry points