Comment Comment by jameshart The bit of react that is f(newState) => UI is the easy part.The bit that is g(state, userInput) => newState is the hard part. In particular managing the scope of that newState.Oh, and sometimes you need to handle h(state, asynchronousData) => newState too.And then comes the fact that even though your f is _pure_, it also has to be _fast_, because it's going to run every time you get a newState. parent jameshart 3 years ago
The bit that is g(state, userInput) => newState is the hard part. In particular managing the scope of that newState.
Oh, and sometimes you need to handle h(state, asynchronousData) => newState too.
And then comes the fact that even though your f is _pure_, it also has to be _fast_, because it's going to run every time you get a newState.