JavaScript reference

This part of the JavaScript section on MDN serves as a repository of facts about the JavaScript language. Read more about this reference.

JavaScript standard built-in objects, along with their methods and properties.

• globalThis
• Infinity
• NaN
• undefined

• eval()
• isFinite()
• isNaN()
• parseFloat()
• parseInt()
• decodeURI()
• decodeURIComponent()
• encodeURI()
• encodeURIComponent()

• Object
• Function
• Boolean
• Symbol

• Error
• EvalError
• RangeError
• ReferenceError
• SyntaxError
• TypeError
• URIError
• AggregateError

• Number
• BigInt
• Math
• Date

• String
• RegExp

• Array
• Int8Array
• Uint8Array
• Uint8ClampedArray
• Int16Array
• Uint16Array
• Int32Array
• Uint32Array
• BigInt64Array
• BigUint64Array
• Float32Array
• Float64Array

• Map
• Set
• WeakMap
• WeakSet

• ArrayBuffer
• SharedArrayBuffer
• DataView
• Atomics
• JSON

• WeakRef
• FinalizationRegistry

• Promise
• GeneratorFunction
• AsyncGeneratorFunction
• Generator
• AsyncGenerator
• AsyncFunction

• Reflect
• Proxy

• Intl
• Intl.Collator
• Intl.DateTimeFormat
• Intl.DisplayNames
• Intl.ListFormat
• Intl.Locale
• Intl.NumberFormat
• Intl.PluralRules
• Intl.RelativeTimeFormat
• Intl.Segmenter

• WebAssembly
• WebAssembly.Module
• WebAssembly.Instance
• WebAssembly.Memory
• WebAssembly.Table
• WebAssembly.CompileError
• WebAssembly.LinkError
• WebAssembly.RuntimeError

JavaScript statements and declarations

• Block
• Empty statement
• break
• continue
• if...else
• switch
• throw
• try...catch

• var
• let
• const

• function
• function*
• async function
• return
• class

• do...while
• for
• for...in
• for...of
• for await...of
• while

• debugger
• export
• import
• label
• with

JavaScript expressions and operators.

• this
• function
• class
• function*
• yield
• yield*
• async function
• await
• []
• {}
• /ab+c/i
• ( )
• null

• Property accessors
• ?. (Optional chaining)
• new
• new.target
• import.meta
• super
• ...obj

• A++
• A--
• ++A
• --A

• delete
• void
• typeof
• +
• -
• ~
• !

• +
• -
• /
• *
• %
• **

• in
• instanceof
• <
• >
• <=
• >=

• ==
• !=
• ===
• !==

• <<
• >>
• >>>

• &
• |
• ^

• &&
• ||
• ??

• (condition ? ifTrue : ifFalse)

• =
• *=
• **=
• /=
• %=
• +=
• -=
• <<=
• >>=
• >>>=
• &=
• ^=
• |=
• &&=
• ||=
• ??=
• [a, b] = [1, 2]
• {a, b} = {a:1, b:2}

• ,

This chapter documents how to work with JavaScript functions to develop your applications.

• arguments
• Arrow functions
• Default parameters
• Rest parameters

• Lexical grammar
• Data types and data structures
• Strict mode
• Deprecated features