JavaScript - iterate array backwards

In this article, we would like to show you how to iterate an array backwards in JavaScript.

1. Using for loop

In this example, we use a simple for loop to iterate the array from the last element (with index = array.length - 1) to the first one by decrementing the iterator (--i).

// ONLINE-RUNNER:browser;

var array = [1, 2, 3];

for (var i = array.length - 1; i >= 0; --i) {
    console.log(array[i]);
}

2. Using reverse() method with forEach()

In this example, we use slice() method to create a shallow copy of an array, then we use reverse() method to reverse the copy. Finally, we iterate the reversed copy of array using forEach().

// ONLINE-RUNNER:browser;

const array = [1, 2, 3];

array.slice().reverse().forEach((item) => console.log(item));

Warning:

This is not a good solution because the array is copied first, then the copy is reversed and it is iterated at the end.

References

1. for - JavaScript | MDN
2. Array.prototype.slice() - JavaScript | MDN
3. Array.prototype.reverse() - JavaScript | MDN
4. Array.prototype.forEach() - JavaScript | MDN