Is there a way to use map() on an array in reverse order with javascript?

Not mutating the array at all, here is a one-liner O(n) solution I came up with:

myArray.map((val, index, array) => array[array.length - 1 - index]);

You can use Array.prototype.reduceRight()

var myArray = ["a", "b", "c", "d", "e"];
var res = myArray.reduceRight(function (arr, last, index, coll) {
    console.log(last, index);
    return (arr = arr.concat(last))
}, []);
console.log(res, myArray)

If you don't want to reverse the original array, you can make a shallow copy of it then map of the reversed array,

myArray.slice(0).reverse().map(function(...