Well I meant the front-end. In the company I work for, we see redux-saga as a poor man's RxJS, and GraphQL, I've heard can sometimes replace both ... i.e., you can make data requests declarative, eliminating the need for aync management. But in the same vein, there's still room for all three in the front-end... which leads to developer overload from having to learn three different technologies.

Redux-saga vs RxJS vs GraphQL... what do you see as the future?

What's the hardest thing to learn about RxJS?