Widely available Supported across all major browsers. Safe to use in production.

Array iterators

The [Symbol.iterator]() method of Array instances implements the iterable protocol and allows arrays to be consumed by most syntaxes expecting iterables, such as the spread syntax and for...of loops. It returns an array iterator object that yields the value of each index in the array.

The initial value of this property is the same function object as the initial value of the Array.prototype.values property.

Arrays

Browser support

Feature Desktop Mobile
Chrome
Edge
Firefox
Safari
Chrome Android
Safari iOS
javascript.builtins.Array.@@iterator
38
12
36
10
38
10
Built-in object
Array.entries

The entries() method of Array instances returns a new array iterator object that contains the key/value pairs for each index in the array.
38
12
28
8
38
8
Array.keys

The keys() method of Array instances returns a new array iterator object that contains the keys for each index in the array.
38
12
28
8
38
8
Array.values

The values() method of Array instances returns a new array iterator object that iterates the value of each item in the array.
66
14
60
9
66
9
1+Supported (version) Not supported ※Has note Sub-feature descriptions sourced from MDN Web Docs (CC BY-SA 2.5)
Notes 6 item(s)
Removed
  • This feature was removed in a later browser version (36)
  • This feature was removed in a later browser version (27)
Implementation note
  • Previously available under a different name: @@iterator (27)
  • A placeholder property named `@@iterator` is used.
  • Previously available under a different name: iterator (17)
  • A placeholder property named `iterator` is used.

Syntax

JAVASCRIPT 
const arr = ['a', 'b', 'c'];

for (const [i, v] of arr.entries()) {
  console.log(i, v); // 0 'a', 1 'b', 2 'c'
}

[...arr.keys()];   // [0, 1, 2]
[...arr.values()]; // ['a', 'b', 'c']

Live demo

ki- and Value Read with entries()

For...of loop in, index and value simultaneous to getout..

PreviewFullscreen

index. onlyread with keys()

Array. all. index(ki-) itere-ta and read..

PreviewFullscreen

Value. onlyread with values()

Array. Elementvalue order to getoutitere-ta read..

PreviewFullscreen

Use cases

  • Using Array iterators

    The [Symbol.

Cautions

  • No specific concerns. Stable across all major browsers.

Accessibility

  • When updating the DOM dynamically, announce important changes to assistive technology with aria-live regions.

Related links