By their very nature almost every single JS library is a hip design trend. The fact that there are so many JS libraries as to warrant a Wikipedia page should prove that point. Most libraries have a specific use case they excel at, but the hype surrounding them usually is more than the usefulness of the library. Claiming that React isn't trendy is kind of like claiming BTRFS isn't trendy. It's being developed and used by Facebook. ReactOS can use it. At the end of the day it will still be niche until it either becomes bloated to provide more usefulness a la JQuery or stops being trendy and just does what it does.