cold-hot-observables.js

/*
 * Cold observable:
 * produce values upon each subscription
 */
const coldObs$ = Rx.Observable.interval(1000)


/*
 * Warm observable:
 * share the value source to all subscriptions,
 * but doesn't start producing before subscriptions exist
*/
const warmObs$ = Rx.Observable.interval(1000)
	.publish() // convert into connectable Observable
 	.refCount() // automate the connecting process when the first observer subscribes
// can be replace with the .share shortcut

/*
 * Hot observable:
 * share the value source to all subscriptions,
 * and produce values no matter if there is any subscription
 */
const hotObs$ = Rx.Observable
	.interval(1000)
	.publish()
hotObs$.connect()


/* Test */
console.clear()

setTimeout(() => {
	hotObs$.subscribe(val => console.log('Subscriber 1: ' + val))

	setTimeout(() =>
		hotObs$.subscribe(val => console.log('Subscriber 2: ' + val))
	, 3000)
}, 3000)