How do you return an Observable of an object where the object has a property built using an http request? [RxJs]

Question

I have a type I want to return from a method that is not the same as one the http request gets - I basically want to assign the results of that http request as a property on the object and return an observable of that object. I understand why the below is not going to work but for the purposes of having code..

getAuditsByObjectAndType<T>(object: T): Observable<IAuditInformation<T>> {
    const auditInfo: IAuditInformation<T> = {
        audits: [],
        object: object
    };

    auditInfo.audits = this.get<IAudit>(`audits?id=${object.id}`)
    return Observable.of(auditInfo)
}

Is there an operator that will help me do what I want please?

Edit:

Got a working implementation but probably could be a lot better..

getAuditsByObjectAndType<T>(object: T): Observable<IAuditInformation<T>> {
    const auditInfo: Observable<IAuditInformation<T>> = Observable.of({
        audits: [],
        object: object
    });

    return this.get<IAudit>(`AuditItems?id=${object.id}`)
        .combineLatest(auditInfo, (audits, info) => {
            info.audits = audits;
            return info
        });
}

Answer 1

You could map the response:

import 'rxjs/add/operator/map';

getAuditsByObjectAndType<T>(object: T): Observable<IAuditInformation<T>> {
  return this.get<IAudit>(`audits?id=${object.id}`)
    .map(audits => ({
      audits,
      object
    }));
}

However typescript has no way of knowing that your T contains an id property, to solve that you could do the following:

interface TheObjectWithAnId {
  id: number;
}

getAuditsByObjectAndType<T extends TheObjectWithAnId>(object: T): Observable<IAuditInformation<T>>