how convert response object property from array in to request rxjs

Issue

API returns an array of JSON Objects.

[
{
    "vacancy": "61a6597b0dc105d6e79a1f30",
    "createdBy": "61aa11644afa183fa28b0792",
    "executor": "61aa20ee25ef06b69920a505",
    "reviewer": "61aa11644afa183fa28b0792",
    "status": "Invited",
    "_id": "61aa213aeaf2af804aa1e591",
    "createdAt": "2021-12-03T13:52:58.772Z",
    "updatedAt": "2021-12-03T13:52:58.772Z"
},
...
]

And I need convert some propertys in to objects by making get request with value. Something like that:

this.http.get<Application>(
      `${environment.API_ENDPOINT}/applications/assigned?status=completed`
    ).pipe(
        map(aplication => 
{
...aplication,
vacancy:this.http.get(`${environment.API_ENDPOINT}/vacancys/`+ aplication.vacancy),
executor:this.http.get(`${environment.API_ENDPOINT}/candidates/`+ aplication.executor)
}
    )

Solution

You need to use a "Higher Order Mapping Operator", which will internally subscribe to an observable and emit its emissions.

In your case, switchMap will work for this. Since you need to make two different calls, we can use forkJoin to create an observable that will emit both results when they are received:

myObj$ = this.http.get<Application>('/applications/assigned').pipe(
    switchMap(aplication => forkJoin({
        vacancy  : this.http.get(`environment.API_ENDPOINT}/vacancys/${vacancy}`),
        executor : this.http.get(`environment.API_ENDPOINT}/candidates/${executor}`)
    }).pipe(
        map(({vacancy, executor}) => ({...aplication, vacancy, executor})
    ))
);

Answered By - BizzyBob