JavaScript Array unshift() method

The unshift() method adds one or more elements to the beginning of an array.

It returns the new length of the array.

JavaScript Array unshift() method changes the original array and its length.

This function increases the length of the existing array by the number of elements added to the array.

In this tutorial, you will learn about the JavaScript Array shift() method with the help of examples.

Syntax

array.unshift(item1, item2, ..., itemN)

item1, item2,…., itemN – The elements to be added.

Return Value

A number. The new length of the array.

Examples

Below are the examples of Array unshift() method.

const array1 = [1, 2, 3];

console.log(array1.unshift(4, 5));
// expected output: 5

console.log(array1);
// expected output: Array [4, 5, 1, 2, 3]

let arr = [4, 5, 6]

arr.unshift(1, 2, 3)
console.log(arr);
// [1, 2, 3, 4, 5, 6]

arr = [4, 5, 6] // resetting the array

arr.unshift(1)
arr.unshift(2)
arr.unshift(3)

console.log(arr)
// [3, 2, 1, 4, 5, 6]

let arr = [1, 2]

arr.unshift(0)               // result of the call is 3, which is the new array length
// arr is [0, 1, 2]

arr.unshift(-2, -1)          // the new array length is 5
// arr is [-2, -1, 0, 1, 2]

arr.unshift([-4, -3])        // the new array length is 6
// arr is [[-4, -3], -2, -1, 0, 1, 2]

arr.unshift([-7, -6], [-5])  // the new array length is 8
// arr is [ [-7, -6], [-5], [-4, -3], -2, -1, 0, 1, 2 ]

let languages = ["Java", "Python", "C"];

// add "JavaScript" at the beginning of the array
languages.unshift("JavaScript");
console.log(languages);

// Output: [ 'JavaScript', 'Java', 'Python', 'C' ]

var languages = ["JavaScript", "Python", "Java", "Lua"];

var count = languages.unshift("C++");
console.log(languages); // [ 'C++', 'JavaScript', 'Python', 'Java', 'Lua' ]
console.log(count); // 5

var priceList = [12, 21, 35];

var count1 = priceList.unshift(44, 10, 1.6);
console.log(priceList); // [ 44, 10, 1.6, 12, 21, 35 ]
console.log(count1); // 6