CB-5703 refactor: optimize data grid onScroll handler #3071
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handleScroll in DataGrid entails small performance degradation due to el.scrollTop, el.clientHeight, el.scrollHeight calls and hence reflow of layout, more on that here: https://gist.github.com/paulirish/5d52fb081b3570c81e3a/565c05680b27c9cfd9f5e971d295cd558c3e1843
What is done:
throttle added to not fire handleScroll on every render, because the main goal of that function is to detect when a user approaches the end of a page = reduce number of calls
Inside the handler the code was refactored in a way that we get scrollTop only once to calculate toBottom and inverse the clause logic and replace early return (!A || !B) with a clause with (A && B) logic to not check B on every call which is also triggering reflow.