array.shift

The shift() method removes the first element from an array and returns that 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

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.

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

See also

• Array.prototype.push()
• Array.prototype.pop()
• Array.prototype.unshift()
• Array.prototype.concat()