Only detecting when elements are above or below viewport

[alexlafroscia]

Is there some way to configure this to only detect when the element is above or below the viewport? I don't care if it went off the page sideways and only want to check if it scrolled off the top.

I was able to achieve the effect by setting viewportTolerance.left and viewportTolerance.right to a really large, arbitrary number, but a way to disable the left-right check altogether would be even better since I figure there are some computations that could then be avoided.

[tomdale]

Could you just use Infinity as the value? I suspect doing an integer comparison is actually faster than having two different code paths from treating it as a separate case.