Does it mutate 😱
Array.prototype.reduceRight
No mutation
Description
The reduceRight() method applies a function against an accumulator and each value of the array (from right-to-left) has to reduce it to a single value.
Array.prototype.reduceRight ( callbackfn [ , initialValue ] )
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/ReduceRight
Example
const array1 = [[0, 1], [2, 3], [4, 5]].reduceRight(
(accumulator, currentValue) => accumulator.concat(currentValue)
);
console.log(array1);
// expected output: Array [4, 5, 2, 3, 0, 1]