JavaScript Array reverse() Method

The Array.reverse() method is a built-in JavaScript function that reverses the order of elements in an array. It modifies the original array so that the first element becomes the last, the second element becomes the second-to-last, and so on.

Syntax

arr.reverse();

Parameters

The reverse() method does not take any parameters.

Return Value

The reverse() method returns the reversed array (the same array, now reversed). It also modifies the original array.

Example 1: Reversing a Simple Array

let arr = [10, 20, 30, 40, 50];
let revArr = arr.reverse();
console.log(revArr); // Output: [50, 40, 30, 20, 10]
console.log(arr);    // Output: [50, 40, 30, 20, 10]

Example 2: Reversing a String Array

let arr = ['HTML', 'CSS', 'JavaScript', 'jQuery'];
let revArr = arr.reverse();
console.log(revArr); // Output: [ 'jQuery', 'JavaScript', 'CSS', 'HTML' ]
console.log(arr);    // Output: [ 'jQuery', 'JavaScript', 'CSS', 'HTML' ]

Example 3: Using reverse() with Nested Arrays

let nestedArr = [[1, 2], [3, 4], [5, 6]];
let revArr = nestedArr.reverse();
console.log(revArr); 
// Output: [[5, 6], [3, 4], [1, 2]]

Example 4: Handling Sparse Arrays

let sparseArray = [10, , 30, , 50];

let revArr = sparseArray.reverse();
console.log(revArr); // Output: [ 50, <1 empty item>, 30, <1 empty item>, 10 ]
console.log(sparseArray); // Output: [ 50, <1 empty item>, 30, <1 empty item>, 10 ]

Example 5: Reversing an Array Without Modifying the Original

To avoid modifying the original array, you can create a copy before reversing:

let arr = [10, 20, 30, 40, 50];
let revArr = [...arr].reverse();
console.log(revArr); // Output: [ 50, 40, 30, 20, 10 ]
console.log(arr);  // Output: [ 10, 20, 30, 40, 50 ]

Using the spread operator (...) creates a shallow copy of the array, preserving the original.

Example 6: Combining with join() to Reverse a String

let str = 'hello';

let revStr = str.split('').reverse().join('');
console.log(revStr); // Output: 'olleh'

Supported Browsers