The values()
method returns a new Array Iterator
object that contains the values for each index in the array.
Syntax
arr.values()
Return value
A new Array
iterator object.
Examples
Iteration using for...of loop
var arr = ['a', 'b', 'c', 'd', 'e']; var iterator = arr.values(); for (let letter of iterator) { console.log(letter); } //"a" "b" "c" "d" "e"
Array.prototype.values is default implementation of Array.prototype[Symbol.iterator].
Array.prototype.values === Array.prototype[Symbol.iterator] //true
Iteration using .next()
var arr = ['a', 'b', 'c', 'd', 'e']; var iterator = arr.values(); iterator.next(); // Object { value: "a", done: false } iterator.next().value; // "b" iterator.next()["value"]; // "c" iterator.next(); // Object { value: "d", done: false } iterator.next(); // Object { value: "e", done: false } iterator.next(); // Object { value: undefined, done: true } iteraror.next().value; // undefined
One-use: the array iterator object is one use or temporary object
example:
var arr = ['a', 'b', 'c', 'd', 'e']; var iterator = arr.values(); for (let letter of iterator) { console.log(letter); } //"a" "b" "c" "d" "e" for (let letter of iterator) { console.log(letter); } // undefined
reason: When next().done=true
or currentIndex>length
the for..of
loop ends. See Iteration protocols.
Value: there are no values stored in the array Iterator object; instead it stores the address of the array used in its creation and so depends on the values stored in that array.
var arr = ['a', 'b', 'c', 'd', 'e']; var iterator = arr.values(); console.log(iterator); // Array Iterator { } iterator.next().value; // "a" arr[1]='n'; iterator.next().value; // "n"
if the values in the array changed the array iterator object values change too.
TODO: please write about why we need it, use cases.
Specifications
Specification |
---|
ECMAScript (ECMA-262) The definition of 'Array.prototype.values' in that specification. |
Browser compatibility
The compatibility table in 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 | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
values | Chrome Full support 66 | Edge Full support 12 | Firefox Full support 60 | IE No support No | Opera Full support 53 | Safari Full support 9 | WebView Android Full support 66 | Chrome Android Full support 66 | Firefox Android Full support 60 | Opera Android Full support 47 | Safari iOS Full support 9 | Samsung Internet Android Full support 9.0 | nodejs
Full support
10.9.0
|
Legend
- Full support
- Full support
- No support
- No support
- See implementation notes.
- See implementation notes.
- User must explicitly enable this feature.
- User must explicitly enable this feature.