What the fuck is React?
There are a number of reactive type libraries and frameworks available (like Angular and Vue). React is unique in the flexibility and lack of configuration it requires. This means a programmer can pick any number of other libraries and tools to extend and enhance the target application. This flexibility means that there are many inventive ways to do the same thing, which of course leads to a lot of reinventing the fucking wheel. The downfall is there are so many options, it’s hard to be able to quantify what ‘experience with React’ really means. One React project can look vastly different than another.
React is pretty fucking popular with open source projects. But it’s not solely limited to open source projects. It also spawned a number of toolsets like React Native, which is mobile application programming but using React as the programming language.