Working with Arrays can be a mess sometimes. In this tutorial, you will learn two ways to reverse an Array in JavaScript.

  • First, using reverse() function
  • Second, using a simple for loop

Using reverse() function

The easiest way to reverse an array in JavaScript is to use the reverse() function. This function is built-in and is supported in all browsers.

The syntax is really easy, you just need to use a dot(.) operator with the array you want to reverse. Making a call to the  reverse() function.

Let’s see few JavaScript examples to reverse the array.

Example 1: Reverse a number Array


let array = [1,2,3,4,5,6,7];  // given array

array.reverse();              // using reverse method
console.log(array);           // [7,6,5,4,3,2,1]

Example 2: Reverse an Array of Objects


let arrayObj = [
    {name:'a', age:1},
    {name:'b', age:2}, 
    {name:'c', age:3}
];

arrayObj.reverse();
console.log(arrayObj); 

// [ { name: 'c', age: 3 }, { name: 'b', age: 2 }, { name: 'a', age: 1 } ]

Whether the array contains a number, String or any objects, the reverse() function will always reverse it.

Note: The original array is overwritten with the value in reverse order.

What if, you want to reverse an array without using a library/in-build function.

Using for Loop to Reverse an Array in JavaScript

As you know, We can use a loop to traverse through an array. Therefore, the value in an array can be obtained in the desired way we want.

Let’s use for loop to reverse an array. Moreover, we need a reverse for loop.

As we want elements starting from the last index to the very first index. And an empty array for storing the values from the original array.


let array = ['a','b','c','d','e'];    // orignal array

let reverseArray= [];                 // an emplty array
let index=0;                          // helper index

for ( let i=array.length-1; i>=0; i--){   // reverse loop
    reverseArray[index]=array[i];         // save values from last index 
    index++;                              // increment index
    
}

console.log(reverseArray);

In the above example, the loop started from (array.length-1) which is the last index, and loops until the index becomes greater than equal (>=)  to zero .i.e the very first index.

Finally, we hope this tutorial helped you to reverse an array. Let us know in the comments if you face any doubts.

Also, You may be interested to learn how to check for Duplicates in Array JavaScript

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