Fix: script error during column resizing on mobile with resizableColumnGuide option enabled (#4757)

[mumberrymountain]

This PR fixes issue #4757. Cannot generate issue on jsfiddle… check sample below instead.

issue4757.zip

Whereas default mobile column resizing behavior of Tabulator is to trigger resizing event during touchmove event, the resizableColumnGuide option changes this behavior so that the event is triggered on touchend event instead.

Generally, touchend event occurs when all fingers are lifted from the display, which means that event.touches.length will be 0 and event.touches[0] will be undefined, and accessing event.touches[0].clientX will cause a script error.

So, I fixed to use e.changedTouches[0].clientX instead when the resizableColumnGuide option is enabled, to avoid script error.

[azmy60]

This is great. But what happens if getResizingClientX returns undefined? maybe it's unlikely? Regardless, I think we should handle the undefined edge case too just to be safe. Maybe log a warning or something?

[mumberrymountain]

@azmy60

Well, think it's unlikely, but no harm in being cautious. I just added a guard for the undefined case.

[azmy60]

Thanks @mumberrymountain !