Web/JavaScript/Reference/Global objects/Map/@@iterator

The initial value of the @@iterator property is the same function object as the initial value of the entries method.

Syntax

myMap[Symbol.iterator]

Return value

The map iterator function, which is the entries() function by default.

Examples

Using [@@iterator]()

const myMap = new Map()
myMap.set('0', 'foo')
myMap.set(1, 'bar')
myMap.set({}, 'baz')

const mapIter = myMap[Symbol.iterator]()

console.log(mapIter.next().value) // ["0", "foo"]
console.log(mapIter.next().value) // [1, "bar"]
console.log(mapIter.next().value) // [Object, "baz"]

Using [@@iterator]() with for..of

const myMap = new Map()
myMap.set('0', 'foo')
myMap.set(1, 'bar')
myMap.set({}, 'baz')

for (const entry of myMap) {
  console.log(entry)
}
// ["0", "foo"]
// [1, "bar"]
// [{}, "baz"]

for (const [key, value] of myMap) {
  console.log(`${key}: ${value}`)
}
// 0: foo
// 1: bar
// [Object]: baz

Specifications

Specification
ECMAScript (ECMA-262)The definition of 'Map.prototype[@@iterator()' in that specification.]

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
`@@iterator`	Chrome Full support 43	Edge Full support 12	Firefox Full support 36 Full support 36 No support 27 — 36 Notes' Alternate Name' Notes' A placeholder property named `@@iterator` is used. Alternate Name' Uses the non-standard name: `@@iterator` No support 17 — 27 Notes' Alternate Name' Notes' A placeholder property named `iterator` is used. Alternate Name' Uses the non-standard name: `iterator`	IE No support No	Opera Full support 30	Safari Full support 10	WebView Android Full support 43	Chrome Android Full support 43	Firefox Android Full support 36 Full support 36 No support 27 — 36 Notes' Alternate Name' Notes' A placeholder property named `@@iterator` is used. Alternate Name' Uses the non-standard name: `@@iterator` No support 17 — 27 Notes' Alternate Name' Notes' A placeholder property named `iterator` is used. Alternate Name' Uses the non-standard name: `iterator`	Opera Android Full support 30	Safari iOS Full support 10	Samsung Internet Android Full support 4.0	nodejs Full support 0.12

Legend

Full support: Full support
No support: No support
See implementation notes.': See implementation notes.
Uses a non-standard name.': Uses a non-standard name.