Learn and focused component-based UI library.Certain features ( e.g routing) are added via community packages.( need to install extra 3rd party libraries to add certain piece of functionality to your app.because react itself really focuses on these components and extra functionality you need to install 3rd party libraries.)
alternative react
complete component-based UI framwork,packed with features.Uses TypeScript. Can be overkill for smaller projects, since it has way more features built in.(Also focuses on components just like React,but it ships more built in features than React.It also embraces TypeScript right from the start since it has way more features built in.But for a large project, on the other hand,you don't need to rely on the community as much,because there's more built into that framework.)
angular + react
complete coponent-based UI framework,includes most core features(ex. routing). A bit less popular than React & Angular. rely less on the community and you don't have as much overload possibly as you might have with Angular,depending on what you build.