fix: (sticky | subheader) - fix little bug on refreshElements()

[mmaestri]

A bug in the refreshElements() function caused malfunction in the subheader component. It applies an order over the self.items array based on the top property calculated in refreshPosition(item).

When sorting, the compare function returns a true/false value (a.top > b.top), but it should return an int value (a.top - b.top). Because of this the self.items array is misordered, self.current, self.prev and self.next are miscalculated and the subheader fails to acknowledge changes in sections.

Changing the compare function solves this issue

[ajoslin]

Interesting, I thought sort would convert true & false to 1 & 0. Maybe it doesn't in certain browsers.

[ajoslin]

Could you sign the CLA so I can merge this?

[ajoslin]

Fixed on my own - I read the API docs for Array.prototype.sort, and the way you're doing it isn't explicitly supported there. So I did the usual -1 or 1.

[mmaestri]

I've already signed the CLA, but travis kept me giving validation errors.

Actually that way is not only supported, but the recommended way to compare integers. If you look at the API docs it says

To compare numbers instead of strings, the compare function can simply subtract b from a. The following function will sort the array ascending:

function compareNumbers(a, b) {
  return a - b;
}