Fix infinite scroll

Some weird check was being done to see if key is numeric.
A recent change from == to === broke this (jshint is not happy about ==),
because the keys are string, so when parsed as int, they didn't ===

Just changed the way of checking if the key is numeric - fixes it.

Change-Id: Ifeecd6dc49b5c4c2ed3b192ba24abe8418210e1f
Merge "Fix infinite scroll"