The keys()
method of Array
instances returns a new array iterator object that contains the keys for each index in the array.
The keys()
method of Array
instances returns a new array iterator object that contains the keys for each index in the array.
None.
A new iterable iterator object.
When used on sparse arrays, the keys()
method iterates empty slots as if they have the value undefined
.
The keys()
method is generic. It only expects the this
value to have a length
property and integer-keyed properties.
Unlike Object.keys()
, which only includes keys that actually exist in the array, the keys()
iterator doesn't ignore holes representing missing properties.
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Chrome | Edge | Firefox | Opera | Safari | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | WebView Android | Deno | Node.js | ||
keys |
38 | 12 | 28 | 25 | 8 | 38 | 28 | 25 | 8 | 3.0 | 38 | 1.0 | 0.12.0 |
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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/keys