[Codewars] Sum of differences in array (8 kyu) / JavaScript

https://www.codewars.com/kata/5b73fe9fb3d9776fbf00009e

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DESCRIPTION:

Your task is to sum the differences between consecutive pairs in the array in descending order.

 

Example

[2, 1, 10]  -->  9

In descending order: [10, 2, 1]

Sum: (10 - 2) + (2 - 1) = 8 + 1 = 9

If the array is empty or the array has only one element the result should be 0 (Nothing in Haskell, None in Rust).

 

코드

function sumOfDifferences(arr) {
  arr.sort((a, b) => b - a);
  return arr[0] - arr[arr.length - 1] || 0;
}