How to sort one array based on how another gets sorted? (Javascript)

Question

I have to create a function to sort a string of numbers based on the 'weight' of each number--the 'weight' is the digits of the numbers added together (the weight of 99 would be 18, the weight of 100 would be 1, etc etc). This means that a string "100 54 32 62" would return "100 32 62 54".

I can get an array of the weights of these numbers just fine by using:

function orderWeight(str) {
    var arr = str.split(" ");
    var sortArr = [];
    arr.forEach(t => sortArr.push(t.split("").map(s => parseInt(s, 10)).reduce(add, 0)));
}

where add is just a generic addition function. For the above example, sortArr would be [1, 9, 5, 8].

What's the best way to sort the array of the original numbers from the string arr based on how the new array of the number weights sortArr gets sorted?

Thanks!

Answer 1

This should do the trick:

var x = '100 54 32 62';

function orderWeight(str) {
  return str.split(' ').sort(function(a, b) {
    return (a.split('').reduce(function(p, c) { return +p + +c; })) > (b.split('').reduce(function(p, c) { return +p + +c; }));
  }).join(' ');
}

var result = orderWeight(x);

Output:

100 32 62 54

UPDATE:

Per suggested by Sterling, here's the same function written in lambda format.

var x = '100 54 32 62';

function orderWeight(str) {
  return str.split(' ').sort((a, b) => a.split('').reduce((p, c) => +p + +c) > b.split('').reduce((p, c) => +p + +c)).join(' ');
}

var result = orderWeight(x);

Note: This is my first time writing Javascript using lambda syntax. Thanks to Sterling for suggesting.