CODEWITHSUNDEEP
angularrxjs
Sandra Willford
Sandra Willford

Reputation: 3789

rxjs conditional observable on reactive form valueChanges

I have an observable that watches for a value change on a reactive form and then qets a new query based on the value change

// this need to run like this...on accountId.value changes if id is > 0 , otherwise accountMessagesDataSource$ = []
this.accountMessagesDataSource$ = this.piForm.get('accountId').valueChanges.pipe(
    switchMap(query => this.pitching.getAccountMessage(query)),
    tap(accountMessages => this.accountMessages = accountMessages)).subscribe();

I need so run this conditionally as described in the comment line above...

Upvotes: 1

Views: 2902

Answers (2)

Ricardo
Ricardo

Reputation: 2487

you can use flatMap to compose your stream

this.accountMessagesDataSource$ = this.piForm.get('accountId').valueChanges.flatMap((id)=> id > 0 ? this.pitching.getAccountMessage(id):of([]))

Upvotes: 0

martin
martin

Reputation: 96891

So you want to run getAccountMessage only when id > 0 and otherwise just return an empty array:

this.accountMessagesDataSource$ = this.piForm.get('accountId').valueChanges
  .pipe(
    switchMap(id => id > 0
      ? this.pitching.getAccountMessage(id)
      : of([])
    ),
    tap(accountMessages => this.accountMessages = accountMessages),
  )
  .subscribe();

Upvotes: 4

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