hammer.js: Hammer.js makes -webkit-overflow-scrolling: touch buggy on iOS

When using Hammer.js on element inside of a container with -webkit-overflow-scrolling: touch on it, scrolling got jumpy and less smooth.

I observed this simply when calling Hammer(element), without any of my own code.

For now I’ve solved it by just stripping out Hammer.js and creating my own touch handling, but I’m still submitting this issue (although I didn’t see it mentioned before).

Note: It’s also worthwhile I think, for Hammer.js to check and make sure the parent container’s scrollTop hasn’t changed between touchstart and touchmove/touchend, to be sure of whether or not it’s a scroll event (iOS doesn’t provide a live scroll event for native scrolling) - this was a huge help in my code.