4 Ways to Empty an Array in JavaScript

Summary: in this tutorial, you will learn the four ways to empty an array in JavaScript.

Suppose you have the following array and want to remove all of its elements:

let a = [1,2,3];Code language: JavaScript (javascript)

The following shows you several methods to make an array empty.

1) Assigning it to a new empty array

This is the fastest way to empty an array:

a = [];

This code assigned the array a to a new empty array. It works perfectly if you do not have any references to the original array.

See the following example:

let b = a;
a = [];
console.log(b); // [1,2,3]Code language: JavaScript (javascript)

In this example, first, the b variable references the array a. Then, the a is assigned to an empty array. The original array still remains unchanged.

2) Setting its length to zero

The second way to empty an array is to set its length to zero:

a.length = 0;

The length property is read/write property of an Array object. When the length property is set to zero, all elements of the array are automatically deleted.

3) Using splice() method

The third way to empty an array is to remove all of its elements using the splice() method as shown in the following example:

a.splice(0,a.length);Code language: CSS (css)

In this solution, the splice() method removed all the elements of the a array and returned the removed elements as an array.

4) Using pop() method

The fourth way to empty an array is to remove each element of the array one by one using the while loop and pop() method:

while(a.length > 0) {
    a.pop();
}Code language: JavaScript (javascript)

This solution is quite trivial and is the slowest one in terms of performance.