> Just be honest that you've looked at it outside of work, understand it but haven't had the chance to use it professionally yet

I can confirm this is true - explained this exact thing to the place i'm working at now... also, react is just a framework. if you understand JS, then you just need to wrap your head around the way it is being used in this particular case... just build a few small sites with it and you'll be further along than a lot of other people.