How to use JavaScript Array.prototype.push() - JavaScript Push Explained with Examples

The JavaScript array method .push() adds one or more new elements to the end of an array and returns the length of the newly expanded array.

Syntax

var array = [1, 2, 3, 4, 5];
array.push(6);

Parameters

.push accepts one or multiple parameters.

Returns

The length of the array is returned by .push()

Description

.push() ‘pushes’ new values onto the end (the right side) of an array.

Examples

Pushing a new element into an array

var array = [1, 2, 3, 4, 5];
var totalArrayElements = array.push(6);

console.log(array);
// Console will output 1, 2, 3, 4, 5, 6

console.log(totalArrayElements);
// Console will output 6

The push() method is used to add one or more new elements to the end of an array. It also returns the new length of the array.

Syntax

arr.push([element1[, ...[, elementN]]])

Parameters

  • elementN The elements to add to the end of the array.

Return value

The new length of the array on which the method was called.

Description

The push() method will push elements to the end of an array. It can take zero or more arguments. If no arguments are provided, it will simply return the current length of the array. If provided one or more arguments, it will add these arguments to the array in the order in which they are written.

This method also returns the new length of the array after the element(s) are pushed to it.

Example:

var myStarkFamily = ['John', 'Robb', 'Sansa', 'Bran'];

Suppose you have an array of the children of House Stark from Game of Thrones. However, one of the members, Arya , is missing. Knowing the code above, you could add her by assigning 'Arya' to the array at the index after the last index like so:

myStarkFamily[4] = 'Arya';

The problem with this solution is that it can’t handle general cases. If you didn’t know beforehand what the length of the array is, you can’t add new elements this way. This is what push() is for. We don’t need to know how long the array is. We just add our element to the end of the array.

myStarkFamily.push('Arya');
console.log(myStarkFamily);  // ['John', 'Robb', 'Sansa', 'Bran', 'Arya']

var newLength = myStarkFamily.push('Rickon');  // oops! forgot Rickon
console.log(newLength);  // 6
console.log(myStarkFamily);  // ['John', 'Robb', 'Sansa', 'Bran', 'Arya', 'Rickon']
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