Theory of comparator function for comparing values in an array.

Hi Kyle,

The compare function doesn't have anything to do with the actual sorting process. This is handled by the sort method using a sorting algorithm. The only job of the compare function is to let the sort method know the relative order of the 2 items that were passed into it.

The sort method will go through the array and it will pass 2 elements at a time to the compare function and the compare function will then return a positive, negative, or zero value which lets the sort method know the relative order of those 2 items.

A negative return value indicates that a should be sorted to a lower index than b

A positive value indicates that b should be sorted to a lower index than a

A zero value indicates that a and b should be considered equal and they may or may not remain in their original order with respect to each other but will be sorted with respect to all other different elements.

You can read more about the sort method and compare function on this mdn page: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort