CODEWITHSUNDEEP
angularrxjsobservable
Mr.FloppyDisk
Mr.FloppyDisk

Reputation: 61

can I pass observable as function parameter?

Can I pass observable to function as a parameter ? I have two observables that get data from backend and I need to filter them out by a lot of conditions. To do not repeat myself I thought about function that will filter observable data and return already filtered one. There will be couple of combineLatest inside as I will be reacting to action streams (values selected on UI). I came up with something like:

    const data1$ = this.service.getData('first');
    const data2$ = this.service.getData('second');

    filterData(input$: Observable<string>) : Observable<string> {

        const filtered$ = combineLatest(input$, this.service.selectedFiltersData$).pipe(...filtering...taping and so on...)
        const filteredBySomethingElse$(filtered$, this.service.anotherSelectedFilters.pipe(...filtering...taping and so on...)

      return filteredBySomethingElse$;
    }

    const filtered1$ = this.filterData(data1$);
    const filtered2$ = this.filterData(data2$);

Example is extremely simplified :)
Is that a good practice ?

Upvotes: 0

Views: 3703

Answers (1)

DeborahK
DeborahK

Reputation: 60518

You could use a more declarative approach. Something like this:

  // Filtered products
  filteredProducts$ = combineLatest([
    this.allProducts$,
    this.filterAction$])
    .pipe(
      // Perform the filtering
      map(([products, filter]) =>
        this.performFilter(products, filter))
    );

Then you don't need to pass Observables into procedures. The code that actually does the filtering takes in the products and filter, not their associated observables.

PLUS: The pipe operations will re-execute every time a new value is emitted into either stream.

See this for more information: https://www.youtube.com/watch?v=Z76QlSpYcck

Upvotes: 3

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