Web/JavaScript/Reference/Global objects/Array/shift

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

Syntax

arr.shift()

Return value

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

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.

Array.prototype.pop() has similar behavior to shift, but applied to the last element in an array.

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:', 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 the next element from an array, until it is empty:

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

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

Specifications

Specification
ECMAScript (ECMA-262)The definition of 'Array.prototype.shift' in that specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
`shift`	Chrome Full support 1	Edge Full support 12	Firefox Full support 1	IE Full support 5.5	Opera Full support 4	Safari Full support 1	WebView Android Full support 1	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 10.1	Safari iOS Full support 1	Samsung Internet Android Full support 1.0	nodejs Full support 0.1.100

Legend

Full support: Full support