I have recently learned that regexes get re-created *1 every time they are executed, unless they are stored in a constant, so this could (at least slightly) improve performance by not having to re-compile the regexes everytime a line is checked, though i have not measured performance..

*1 apparently it is only compiled once but every time they are executed a new regexp object is created and needs to be gb collected

MDN Guide: Regular Expressions
also see this stackoverflow thread

probably should do some measurements just to be sure, but from my slight look it should be at least somewhat better for V8