It's much better to do this earlier. If you're asking v8 to optimise, say, the whole of React on a mobile device before first paint, that's definitely going to

It's much better to do this earlier. If you're asking v8 to optimise, say, the whole of React on a mobile device before first paint, that's definitely going to be slower than having the same optimisations done before V8 needs to parse/optimise it!