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Question

I'm new with Angular 2. I have situation when one promise into another, I have error messages working with http.post into following code. How should I use

.then

here?

export class KeyValue {
    constructor(
        private OrganizationId: string,
        private OrganizationFriendlyName: string) {
    }
}

export interface IComponentData {
    title: string;
    signInUrl: string;
    orgFriendlyName: KeyValue[];
}

@Injectable()
export class Api {
    title: string = '<Application Name>';
    signInUrl: string = '';
    http: Http;
    orgFriendlyName: KeyValue[];

    postData(): Promise<KeyValue[]> {
        var headers = new Headers();
        headers.append('Content-Type', 'application/json'); 

        return this.http.post('url', JSON.stringify({}), { headers: headers })
            .then(function(res) {
            .map(res => res.json());
            .subscribe((res: KeyValue[]) => this.orgFriendlyName = res);
        });

    }

    getComponentData(): Promise<IComponentData> {
        return this.postData().then(() => {
            return new Promise((resolve, reject) => {
                resolve({
                    title: this.title,
                    signInUrl: this.signInUrl,
                    orgFriendlyName: this.orgFriendlyName
                });
            });
        });
    }
}

How should I get data from POST request?

Answer 1

I would refactor your code using the toPromise method of observable this way:

postData(): Promise<KeyValue[]> {
  var headers = new Headers();
  headers.append('Content-Type', 'application/json'); 

  return this.http.post('url', JSON.stringify({}), { headers: headers })
      .map(res => res.json())
      .toPromise();
  });
}

This way you will be able to call the then method on it within the getComponentData method:

getComponentData(): Promise<IComponentData> {
  return this.postData().then((data) => {
    return {
      title: data.title,
      signInUrl: data.signInUrl,
      orgFriendlyName: data.orgFriendlyName
    };
  });
}