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Array.prototype.keys()

Metoda keys() zwraca nowy obiekt typu Array Iterator zawierający indeksy kolejnych elementów tablicy.

var arr = ['a', 'b', 'c'];
var iterator = arr.keys();

console.log(iterator.next()); // { value: 0, done: false }
console.log(iterator.next()); // { value: 1, done: false }
console.log(iterator.next()); // { value: 2, done: false }
console.log(iterator.next()); // { value: undefined, done: true }

Składnia

arr.keys()

Zwracana wartość

Nowy iterator dla typu Array.

Przykłady

Iterator nie ignoruje dziur

var arr = ['a', , 'c'];
var sparseKeys = Object.keys(arr);
var denseKeys = [...arr.keys()];
console.log(sparseKeys); // ['0', '2']
console.log(denseKeys);  // [0, 1, 2]

Specyfikacje

Specyfikacja Status Komentarz
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Array.prototype.keys' in that specification.		 Standard Pierwsze wystąpienie.
ECMAScript (ECMA-262)
The definition of 'Array.prototype.keys' in that specification.		 Living Standard  

Kompatybilność z przeglądarkami

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help! (en-US)
Feature Chrome Firefox (Gecko) Edge Internet Explorer Opera Safari
Basic support 38 28 (28) (Yes) No support 25 7.1
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support 28.0 (28) No support No support 8.0

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