[Javascript] Broadcaster + Operator + Listener pattern -- 13. Repeat When Done with a Repeat Operator

import { addListener, done, forOf } from "./broadcasters";

const log = console.log;

// only when listener receive DONE event
// then broadcaster should trigger the listener again
// otherwise, keep emit value
let repeat = (broadcaster) => (listener) => {
  let cancel;
  let repeatListener = (value) => {
    // when it is doen event
    if (value === done) {
      // because it is repeated event
      // need to cancel previous one
      if (cancel) {
        cancel();
      }
      // broadcaster should trigger the listener again
      cancel = broadcaster(repeatListener);
      return;
    }
    // otherwise, keep emitting value
    listener(value);
  };
  cancel = broadcaster(repeatListener);

  return () => cancel();
};

// Only when 'whenBroadcater' happen then do the repeat logic
let repeatWhen = (whenBroadcaster) => (mainBroadcaster) => (listener) => {
  let mainCancel;
  let whenCancel;
  let repeatListener = (value) => {
    if (value === done) {
      if (mainCancel) {
        mainCancel();
      }
      whenCancel = whenBroadcaster(() => {
       // cancel previous when broadcaster 
        whenCancel();
        mainCancel = mainBroadcaster(repeatListener);
      });
    }
    listener(value);
  };
  mainCancel = mainBroadcaster(repeatListener);

  return () => {
    mainCancel();
    whenCancel();
  };
};

const inputClick = addListener("#input", "click");
const printCat = forOf("cat");
const repeatCatOnClick = repeatWhen(inputClick)(printCat);
const cancel = repeatCatOnClick(log);

setTimeout(() => {
  cancel();
}, 3000);