Loader state machine component

loader.js

export function Loader() {
 function* Loading() {
   yield on("error", Failed);
   yield on("timeout", TimedOut);
   yield on("abort", Aborted);
   yield on("success", Loaded);
 }
 function* Failed() {}
 function* TimedOut() {}
 function* Aborted() {}
 function* Loaded() {}

 return Loading;
}