[RxJS] Split an RxJS observable conditionally with windowToggle

There are variants of the window operator that allow you to split RxJS observables in different ways. In this lesson we will explore the windowToggle variant and see one of its use cases in user interfaces.

const clockObs = Rx.Observable.interval(1000);
const downObs = Rx.Observable.fromEvent(document, 'mousedown');
const upObs = Rx.Observable.fromEvent(document, 'mouseup');

const source = clockObs
  .windowToggle(downObs, () => upObs)
  .switch()
  .subscribe(console.log);

/*
--0--1--2--3--4--5--6--7--8--9--
          windowToggle
----------D--------U-------------
          \
          -3--4--5-|
          
          switch / mergeAll
          
-----------3--4--5---------------          
*/