Angular 4 setTimeout does not wait

Since you are using Angular you can probably do this in a much simpler way using takeWhile:

Observable.interval(10000)    .takeWhile(() => !stopCondition)    .subscribe(i => {         // This will be called every 10 seconds until `stopCondition` flag is set to true    })

Yes, you're doing it wrong: you have a loop telling 4 times in a row to execute timer() 3 seconds later, from now.

To do what you want, you would have to reschedule the next timer each time timer() is called, or, more simply, to use setInterval():

let count = 0;const interval = window.setInterval(() => {    this.timer();    count++;    if (count >= 4) {        window.clearInterval(interval);    }}, 3000); 

Note that, since you're using angular, using observables would be muuuch easier:

Observable.interval(3000).take(4).subscribe(() => this.timer());

I did it with Angular 6. This code requests every 5 seconds to get the progress of rendering. It will stops sending request when the progress reaches %100.

import {interval} from "rxjs";getProgress(searchId): void{const subscription = interval(5000)  .subscribe(()=>{    //Get progress status from the service every 5 seconds    this.appService.getProgressStatus(searchId)      .subscribe((jsonResult:any)=>{          //update the progress on UI           //cancel subscribe until it reaches %100          if(progressPercentage === 100)            subscription.unsubscribe();        },        error => {          //show errors        }      );  });}