CODEWITHSUNDEEP
angulartypescriptobservable
astralmaster
astralmaster

Reputation: 2465

Returning modified Observable value Angular 6

Consider the following example:

 login(context: LoginContext): Observable<Credentials> {

    let credentials = JSON.stringify(context);

    this.httpClient.post("http://localhost:64636/api/Account/login", credentials, {
      headers: new HttpHeaders({
        "Content-Type": "application/json"
      })
    }).subscribe(response => {
      let token = (<any>response).token;

      const data = {
        username: context.username,
        token: token
      };

      this.setCredentials(data, context.remember);
      return of(data);

    }, err => {

    });


  }

Here what I am trying to achieve is to encapsulate the data that is received from the httpClient and return it, but this is done after the execution of httpClient is complete. The compiler tells me that "a function whose declared type is neither 'void' nor 'any' must return a value" and rightfully so. My question is, how to resolve such issue when the parent observable must wait for the httpClient.post() observable to finish its task?

Upvotes: 1

Views: 506

Answers (1)

Martin Parenteau
Martin Parenteau

Reputation: 73731

Use the map operator to modify the value returned by an Observable:

login(context: LoginContext): Observable<Credentials> {

  let credentials = JSON.stringify(context);

  return this.httpClient.post("http://localhost:64636/api/Account/login", credentials, {
    headers: new HttpHeaders({
      "Content-Type": "application/json"
    })
  }).pipe(
    map(response => {
      let token = (<any>response).token;
      const data = {
        username: context.username,
        token: token
      };
      this.setCredentials(data, context.remember);
      return data;
    })
  );
}

Upvotes: 1

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