Function toggleMap

⏯ Begins a new subscription to the mapped Observable, only if there is no current subscription.

• Any current Subscription is terminated.
• Use when cancelability is important, like a video player tapped both to start and stop.

Example

```

• const switch = new Subject();
• const light = switch.pipe(toggleMap(() => new Observable(o => {
• console.log('connected: true');
• return () => console.log('connected: false');
• }))).subscribe()
• switch.next(); // connected: true
• switch.next(); // connected: false
• ```