The keys()
method returns a new Iterator
object that contains the keys for each element in the Map
object in insertion order.
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Syntax
myMap.keys()
Return value
A new Map
iterator object.
Examples
Using keys()
var myMap = new Map(); myMap.set('0', 'foo'); myMap.set(1, 'bar'); myMap.set({}, 'baz'); var mapIter = myMap.keys(); console.log(mapIter.next().value); // "0" console.log(mapIter.next().value); // 1 console.log(mapIter.next().value); // Object
Specifications
Specification |
---|
ECMAScript (ECMA-262) The definition of 'Map.prototype.keys' in that specification. |
Browser compatibility
The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Desktop | Mobile | Server | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
keys | Chrome Full support 38 | Edge Full support 12 | Firefox Full support 20 | IE No support No | Opera Full support 25 | Safari Full support 8 | WebView Android Full support 38 | Chrome Android Full support 38 | Firefox Android Full support 20 | Opera Android Full support 25 | Safari iOS Full support 8 | Samsung Internet Android Full support 3.0 | nodejs Full support 0.12 |
Legend
- Full support
- Full support
- No support
- No support