Our volunteers haven't translated this article into Italiano yet. Join us and help get the job done!
You can also read the article in English (US).

The shift() method removes the first element from an array and returns that removed element. This method changes the length of the array.

var a = [1, 2, 3];
var b = a.shift();

console.log(a); // [2, 3]
console.log(b); // 1



Return value

The removed element from the array; undefined if the array is empty.


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.


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:', JSON.stringify(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

Using shift() method in while loop

The shift() method is often used in condition inside while loop. In the following example every iteration will remove next element from an array, untill it will be empty:

var names = ["Andrew", "Edward", "Paul", "Chris" ,"John"];

while( (i = names.shift()) !== undefined ) {
// Andrew, Edward, Paul, Chris, John


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.
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Array.prototype.shift' in that specification.
ECMAScript Latest Draft (ECMA-262)
The definition of 'Array.prototype.shift' in that specification.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support1 Yes15.5 Yes Yes
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes4 Yes Yes ?

See also

Tag del documento e collaboratori

 Ultima modifica di: wbamberg,