I do not have time to provide a PR atm, but this should be fixxed really simple.

if (category === undefined || action === undefined || trim(String(category)).length === 0 || trim(String(action)).length === 0) { ...

@fdellwing just fyi to make JSLint in the tests happy we will need to use something like typeof value === "undefined". Should be definitely an easy fix

Maybe not the right place for that, you can DM me in the forums with an answer if you want:

I'm not experienced with JSLint, what is it's problem with ˋvalue === undefinedˋ? This is perfectly valid JS, isn't it?

It definitely is valid. It's just when the JS tests run, there is a test to check if JSLint is "happy" and it usually complains about it.

whats about
if (!category || ...
and:
if you use trim, why not here also?
buildEventRequest(trim(String(category)), trim(String(action)), name, value),

Never use something like !category if you have no control over the input, you are asking for trouble.

To make it more clear what I mean, check the output of the following lines (both being empty strings):

("") ? "truthey" : "falsey";
(new String("")) ? "truthey" : "falsey";