The easiest way to move or insert a node before an optional reference node, implemented following the standard decision to throw out of the blue when moving a node is not possible.
Please read reasons and undesired side-effects if you care about those.
There is no standard way to know if a node can be moved, as opposite of being instered. There are checks that might be needed before performing a move operation described in here but because the DOM API is a moving target, no matter how many manual checks we do outside internal APIs, to be sure the operation is successful we also need to try/catch that operation regardless.
Accordingly, nobody wins so ... why bother? This module simply does that try/catch without second thoughts and that's it, promoting reusable code as opposite of finding the same try/catch dance all over the Web.
Feel free to ignore it or use it any time you think you have moveBefore covered, as it will surprise and backfire if you don't try/catch around, that's the standard decision.