CODEWITHSUNDEEP
angulartypescriptrxjs
Armando_pagano
Armando_pagano

Reputation: 148

how to pass data between services functions in Anguar

what I am trying to do here is making a store() function in my front-end that creates a new question inside the database but I need to add the. active user id to that question's data before sending everything to the back-end.

this is the actual store() function inside my questionsService

store(title : string, content: string, category_id : number): Observable<QuestionsInterface>{

   let user_id : Observable<number>
   user_id = this.authService.getUser()
      .pipe(map(user => {
        return user.id
      })) 
    return this.http.post<QuestionsInterface>(this.baseUrl, {
      title,
      content,
      user_id : user_id,
      category_id
    })
  }

the this.authService.getUser() returns an Observable that emits the actual user's data trough an interface

the problem here is that I cannot find out how should a treat the this.authService.getUser()output to assign it to the user_id variable`

do I need to subscribe to the output?

is there a way not to use subscribe? considering that is a single json response that is sent by the api

Upvotes: 0

Views: 57

Answers (1)

peinearydevelopment
peinearydevelopment

Reputation: 11474

I believe what you want to use is switchMap. getUser returns an Observable, switchMap will take the emission from that observable and pass the return object from that and create another Observable to be listened to from it.

store(title : string, content: string, category_id : number): Observable<QuestionsInterface>{    
    return this.authService
               .getUser()
               .pipe(
                   take(1),
                   switchMap(user => this.http.post<QuestionsInterface>(
                       this.baseUrl,
                       {
                           title,
                           content,
                           user_id : user.id,
                           category_id
                       }));
}

Upvotes: 2

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