If speed and compilation is a concern, let's start with having proper types in javascript. That will speed things up a whole lot faster and save a lot of battery than this.
I am not saying this won't make things faster. There are many things you can do to make things faster but this really is such a niche feature (for web based apps).
> If speed and compilation is a concern, let's start with having proper types in javascript.
That is a much harder problem, especially since you brought up performance. Getting the interaction between dynamically typed and statically typed code to work in a way that's both easy and natural to use and allows compilers to get significant benefits from the statically typed code is an unsolved research problem.
Yes, it is. However, it's relatively easy to implement and the performance improvements and battery savings are fairly huge. All things considered, it's a pretty good deal.
I am not saying this won't make things faster. There are many things you can do to make things faster but this really is such a niche feature (for web based apps).