Array.prototype.keys()
The keys() method returns a new Array
Iterator object that contains the keys for each index in the array.
Syntax
keys()
Return value
A new Array iterator object.
Examples
Key iterator doesn't ignore holes
const arr = ['a', , 'c'];
const sparseKeys = Object.keys(arr);
const denseKeys = [...arr.keys()];
console.log(sparseKeys); // ['0', '2']
console.log(denseKeys); // [0, 1, 2]
Specifications
| Specification |
|---|
| ECMAScript Language Specification # sec-array.prototype.keys |
Browser compatibility
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