What I'm saying is that the pipe (or) "|" is a cheap way to combine regexps. It has its limitations, but its better than an O(n) search through an array. The regexp parser can create an NFA that is far more optimized.
In JS, "far more" isn't quite that dramatically far as in other dynamic language runtimes. See http://jsperf.com/regex-list-vs-full
I don't think this was an unreasonable implementation. Sure, it could be optimized, but no-one needed it enough to do the work. (Even Netflix didn't need a faster matcher, they needed a matcher that didn't slow down between the 1st match and the nth.)