RxJS / Angular Observables use 1 or multiple pipes?

Question

Having the following (just a quick example):

observable.pipe(map( s => s.anything ))
          .pipe(filter(t => t > 5))
          .pipe(map( t => t+5))
          .subscribe( XXX )

Why should I use 1 pipe instead?

    observable.pipe(
                   map( s => s.anything ), filter(t => t > 5),map( t => t+5))
              .subscribe( XXX )

To me, the code is more nice and readable in the first case. But no idea if that affects the behaviour anyway.

Answer 1

You should use a single pipe for that purpose. Having multiple pipes will serve no purpose or benefit, as the usage of pipes is to combine RxJS functional operators into a single chain.

In order to make it more readable, you can do something like this, instead of having all the operators on 1 single line of code.

observable
  .pipe(
    map(s => s.anything ),
    filter(t => t > 5),
    map(t => t+5)
  ).subscribe(res => {
    // do the rest
});

The official Angular guide has a good summary on the usage of pipes and other operators. You may read up more about it over here. You should read up about pipeable operators over here as well.