javascript - Sorting / compare in Chrome vs Firefox

Question

I have the latest Firefox and Chrome running on Windows 10. I believe the same issue exists on Mac.

When I have a compare function can someone explain to me why when I console.log a and b, the results in Chrome are the reverse of the results in Firefox. Oddly, though, the sorted result is the same which doesn't make any sense:

var arr = [3, 1, 2];
var sorted_arr = arr.sort(function(a, b) {
  console.log("a, b = ", a, b);
  return a - b;
});

console.log(sorted_arr);

Answer 1

Browsers are allowed to implement sort however they want, and you should not rely on any particular order of the calls to the comparison function.