Javascript Reversing arrays
.reverse is used to reverse the order of items inside an array.
Example for .reverse:
[1, 2, 3, 4].reverse();Output
[4, 3, 2, 1]
Please note that .reverse(Array.prototype.reverse) will reverse the array in place. Instead of
returning a reversed copy, it will return the same array, reversed.
var arr1 = [11, 22, 33];
var arr2 = arr1.reverse();
console.log(arr2); // [33, 22, 11]
Output
[33, 22, 11]
You can also reverse an array 'deeply' by:
function deepReverse(arr) {
arr.reverse().forEach(elem => {
if(Array.isArray(elem)) {
deepReverse(elem);
}
});
return arr;
}
Example for deepReverse:
var arr = [1, 2, 3, [1, 2, 3, ['a', 'b', 'c']]];
deepReverse(arr);Output
arr // -> [[['c','b','a'], 3, 2, 1], 3, 2, 1]