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v3.45-docs (default)
v3.45-docs
Usage
Supported engines and compatibility data
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 / Array.prototype.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.isError
Explicit Resource Management
Float16 methods
Iterator helpers
Object.values / Object.entries
Object.fromEntries
Object.getOwnPropertyDescriptors
Accessible Object.prototype.hasOwnProperty
String padding
String.prototype.matchAll
String.prototype.replaceAll
String.prototype.trimStart / String.prototype.trimEnd
RegExp s (dotAll) flag
RegExp named capture groups
RegExp escaping
Promise.allSettled
Promise.any
Promise.prototype.finally
Promise.try
Promise.withResolvers
Symbol.asyncIterator for asynchronous iteration
Symbol.prototype.description
Well-formed JSON.stringify
Well-formed unicode strings
New Set methods
Math.sumPrecise
Stage 3 proposals
Iterator sequencing
Map upsert
JSON.parse source text access
Symbol.metadata for decorators metadata proposal
Stage 2.7 proposals
Joint iteration
Stage 2 proposals
AsyncIterator helpers
Iterator.range
Array.isTemplateObject
Number.prototype.clamp
String.dedent
Symbol predicates
Symbol.customMatcher for extractors
Iterator chunking
Stage 1 proposals
Observable
New collections methods
.of and .from methods on collection constructors
compositeKey and compositeSymbol
Array filtering
Array deduplication
DataView get / set Uint8Clamped methods
Number.fromString
String.cooked
String.prototype.codePoints
Symbol.customMatcher for pattern matching
Stage 0 proposals
Function.prototype.demethodize
Function.{ isCallable, isConstructor }
Pre-stage 0 proposals
Reflect metadata
Web standards
self
structuredClone
Base64 utility methods
setTimeout and setInterval
setImmediate
queueMicrotask
URL and URLSearchParams
DOMException
iterable DOM collections
Iteration helpers
Missing polyfills
Playground
Changelog
Theme
v3.45-docs
v3.45-docs (default)
v3.45-docs
Usage
Supported engines and compatibility data
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 / Array.prototype.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.isError
Explicit Resource Management
Float16 methods
Iterator helpers
Object.values / Object.entries
Object.fromEntries
Object.getOwnPropertyDescriptors
Accessible Object.prototype.hasOwnProperty
String padding
String.prototype.matchAll
String.prototype.replaceAll
String.prototype.trimStart / String.prototype.trimEnd
RegExp s (dotAll) flag
RegExp named capture groups
RegExp escaping
Promise.allSettled
Promise.any
Promise.prototype.finally
Promise.try
Promise.withResolvers
Symbol.asyncIterator for asynchronous iteration
Symbol.prototype.description
Well-formed JSON.stringify
Well-formed unicode strings
New Set methods
Math.sumPrecise
Stage 3 proposals
Iterator sequencing
Map upsert
JSON.parse source text access
Symbol.metadata for decorators metadata proposal
Stage 2.7 proposals
Joint iteration
Stage 2 proposals
AsyncIterator helpers
Iterator.range
Array.isTemplateObject
Number.prototype.clamp
String.dedent
Symbol predicates
Symbol.customMatcher for extractors
Iterator chunking
Stage 1 proposals
Observable
New collections methods
.of and .from methods on collection constructors
compositeKey and compositeSymbol
Array filtering
Array deduplication
DataView get / set Uint8Clamped methods
Number.fromString
String.cooked
String.prototype.codePoints
Symbol.customMatcher for pattern matching
Stage 0 proposals
Function.prototype.demethodize
Function.{ isCallable, isConstructor }
Pre-stage 0 proposals
Reflect metadata
Web standards
self
structuredClone
Base64 utility methods
setTimeout and setInterval
setImmediate
queueMicrotask
URL and URLSearchParams
DOMException
iterable DOM collections
Iteration helpers
Missing polyfills
globalThis
Specification
Proposal repo
Built-ins signatures
let globalThis: GlobalThisValue;
Entry points
core-js/proposals/global-this
Built-ins signatures
Entry points