Array.prototype.shift()
The shift()
method removes the first element from an array and returns that element. This method changes the length of the array.
Syntax
<var>arr</var>.shift()
Return value
The removed element.
Description
The shift
method removes the element at the zeroeth index and shifts the values at consecutive indexes down, then returns the removed value. If the length
property is 0, undefined
is returned.
shift
is intentionally generic; this method can be called or applied to objects resembling arrays. Objects which do not contain a length
property reflecting the last in a series of consecutive, zero-based numerical properties may not behave in any meaningful manner.
Examples
Removing an element from an array
The following code displays the myFish
array before and after removing its first element. It also displays the removed element:
var myFish = ['angel', 'clown', 'mandarin', 'surgeon']; console.log('myFish before: ' + myFish); // "myFish before: angel,clown,mandarin,surgeon" var shifted = myFish.shift(); console.log('myFish after: ' + myFish); // "myFish after: clown,mandarin,surgeon" console.log('Removed this element: ' + shifted); // "Removed this element: angel"
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 3rd Edition (ECMA-262) | Standard | Initial definition. Implemented in JavaScript 1.2. |
ECMAScript 5.1 (ECMA-262) The definition of 'Array.prototype.shift' in that specification. |
Standard | |
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Array.prototype.shift' in that specification. |
Standard | |
ECMAScript 2017 Draft (ECMA-262) The definition of 'Array.prototype.shift' in that specification. |
Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | 1.0 | 1.0 (1.7 or earlier) | 5.5 | (Yes) | (Yes) |
Feature | Android | Chrome for Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) | (Yes) |
See also
License
© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/javascript/reference/global_objects/array/shift