CODEWITHSUNDEEP
angularrxjsobservablengrx
Shakibuz_Zaman
Shakibuz_Zaman

Reputation: 270

What is the best way to handle dependent observable subscription in angular?

I have an observable which emits some id and i have to make an another subscription which uses the emitted ids. What is the best way to handle this subscription. I know a solution like subscribing the second observable inside the the first observable subscription. Like below -


observable1$.subsctipe(id=>{ 
   this.store.pipe(select(some_selector, id)).subscribe(value=>{
      //some business
   })
})

Is this solution has any bad effect like memory leaks? And is there any other better way to do this?

Upvotes: 0

Views: 930

Answers (1)

kai
kai

Reputation: 6887

The bad effect of this thing is that you have two subscriptions to keep track of. You have to unsubscribe both to clean up.

observable1$.pipe(mergeMap(id => 
   this.store.pipe(select(some_selector, id))
).subscribe(value => {
   //some business
})

Better do it like this. Then you have only one subscription to release if the component destroys. This is not the case with your current implementation.

I also assume that you dont want to keep listening to your store with the old id if observable1$ has already emittet a new id. If thats the case, you can replace mergeMap with switchMap. Btw flatMap is an alias for mergeMap.

Upvotes: 2

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