How to loop .subscribe observable

Question

I'm currently trying to make a function where it loops and by using .subscribe I'm getting an array object each time so that later on I can push the data inside an another array. The loop works but the problem is that the results is not what I want because the .subscribe part is printing the first array and then for the rest it's giving me null arrays whereas it suppose to print 20x the same array. I currently started experimenting with angular and to my knowledge of other languages I don't think that it's working good by first printing "Test"x20 and after goes inside the subscribe and printing.

Function:

testingFunction()
{
   let i: number = 0;

   while(i < 20){

   console.log("Test");

   this.testService.getAll().subscribe((object: any[]) => {
      console.log(object);
   })

    i++;
  }
}

wentjun · Accepted Answer · 2020-01-25 11:28:29Z

2

Since you are using Angular, you can make use of RxJS operators to handle this scenario. The forkJoin operator will allow you to wait for the while loop operation to be completed before returning all the observables.

This is how you can make use of the operator:

testingFunction() {
   let i: number = 0;
   const observablesList = []; 

   while(i < 20){
     observablesList.push(this.testService.getAll());
     i++;
   }
   forkJoin(observablesList).subscribe((response) => {
     console.log(response);
   });
}

edited Jan 25, 2020 at 11:28

answered Jan 25, 2020 at 11:15

wentjun

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2 Comments

MexicoBoy Over a year ago

Although this answer worked in grouping the arrays, I'm still having the first array visible and the others as null

wentjun Over a year ago

@MexicoBoy in that case, what does getAll() do? I am guessing it is some other part in your codebase that is giving you an issue

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