This._ngZone.onMicrotaskEmpty.first () - code explanation

Question

Someone helped me with the problem of asynchrony almost 2 months ago, it works very well (and since then I added it to the list), but I still have this code in my program, which I'm not quite sure what it does .

Source:

constructor(private ngZone: NgZone) { }

ngOnInit() { 
   this.getPosts()
     .subscribe(x => { 
        this.apidata = x;
        this.ngZone.onMicrotaskEmpty.first().subscribe(() => {
          this.largestHeight(); 
        });
      });
}

Now it is so difficult to get documentation on this, and I have tried for the past two months. They just give a definition, but not real examples. The actual line will bethis.ngZone.onMicrotaskEmpty.first().subscribe(()

1) So, ngZone basically gets access to the zone in which you are busy, and I understand that 70%

2) onMicrotaskEmpty "Reports when there are no more microtasks in the current rotation of the virtual machine.

• a) -, VM " "? .
• b) , ? , , , ?
• c) , Angular . , "" ? Angular ?
• d) onMicrotaskEmpty onStable, . ? ( , ).

3) first() , , w3school: " first() ". , . console.dir .log, , , [object Object]. , ?

4) subscribe() , . , / promises. , , , ? , - , ?

, , , , , , ...: P

Answer 1

Vm , , , Zone Angular - , . .

this.ngZone.onMicrotaskEmpty - Observable, first() - , , ,

subscribe() - ,

- Rxjs,