Earlier quoted context omitted.
The risk behind Preact isn't the API . Remember, this is a discussion about patents , so what matters is fundamental concepts and algorithms. The most likely thing for Facebook to patent is the concept of a virtual DOM that's diffed to apply updates to the real DOM. IF they have such a patent (and apparently they don't), then any library that has a vdom implementation infringes, including Preact. Of course, if they D…
I'm pretty sure that the concept (or implementation) of virtual dom wasn't invented as a part of React. IANAL but I don't think they could patent it. Ignoring specific optimizations, a virtual dom algorithm is fairly simple.
The patent issue is really not a big deal with React; the real concern is philosophical.