The initial value of the @@iterator property is the same function object as the initial value of the values() property.
arr[Symbol.iterator]()
The array iterator function, which is the values() function by default.
for...of loopvar arr = ['w', 'y', 'k', 'o', 'p'];
var eArr = arr[Symbol.iterator]();
// your browser must support for..of loop
// and let-scoped variables in for loops
for (let letter of eArr) {
console.log(letter);
}
var arr = ['w', 'y', 'k', 'o', 'p']; var eArr = arr[Symbol.iterator](); console.log(eArr.next().value); // w console.log(eArr.next().value); // y console.log(eArr.next().value); // k console.log(eArr.next().value); // o console.log(eArr.next().value); // p
| Specification | Status | Comment |
|---|---|---|
| ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Array.prototype[@@iterator]()' in that specification. | Standard | Initial definition. |
| ECMAScript 2017 Draft (ECMA-262) The definition of 'Array.prototype[@@iterator]()' in that specification. | Draft |
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|
| Basic support | 38 | 36 (36) [1] | No support | 25 | No support |
| Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|
| Basic support | No support | No support | 36.0 (36) [1] | No support | 25 | No support |
[1] From Gecko 17 (Firefox 17 / Thunderbird 17 / SeaMonkey 2.14) to Gecko 26 (Firefox 26 / Thunderbird 26 / SeaMonkey 2.23 / Firefox OS 1.2) the iterator property was used (bug 907077), and from Gecko 27 to Gecko 35 the "@@iterator" placeholder was used. In Gecko 36 (Firefox 36 / Thunderbird 36 / SeaMonkey 2.33), the @@iterator symbol got implemented (bug 918828).
Array.prototype.keys()Array.prototype.entries()Array.prototype.forEach()Array.prototype.every()Array.prototype.some()Array.prototype.values()
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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/@@iterator