/*** Helper Functions ***/

​

const showTyping = () => $('.typing').text('User is typing...');

const showIdle = () => $('.typing').text('');

const updateTimer = (x) => $('.timer').text(x);

​

/*** Program Logic ***/

​

// declare shared streams

const inputEvents$ = Rx.Observable.fromEvent($('#input'), 'input').share();

const idle$ = inputEvents$.debounceTime(1000).share();

​

// intermediate stream for counting until idle

const countUntilIdle$ = Rx.Observable

  .interval(1000)

  .do(console.log)

  .startWith('start counter') // first tick required so we start watching for idle events right away

  .takeUntil(idle$);

​

// build clock stream

const clock$ = inputEvents$

  .exhaustMap(() => countUntilIdle$)

  .scan((acc) => acc + 1, 0);

​

/*** Subscribe to Streams ***/

idle$.subscribe(showIdle);

inputEvents$.subscribe(showTyping);

clock$.subscribe(updateTimer);

​