How to merge 2 Observables in nestjs Interceptor()?

I am developping a nestjs interceptor to geolocate an address I am sending throught a rest API. Here is the code:

export class PointsInterceptor implements NestInterceptor {
  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {

    var monaddress = context.switchToHttp().getRequest().body
    const geoPremiseToObservable = from(geocoder.geocode(monaddress));
    geoPremiseToObservable.subscribe(value => console.log(JSON.stringify(value)));

    return next.handle().pipe(map(value => console.log(value)))
  }

}

The result of this code is:

a JSON coming from the http response:

{
  address: '123, avenue des Champs Elysées, 75008 PARIS',
  _id: new ObjectId("64bd089088f925780705bbbd"),
  __v: 0
}

An Object coming from geoCoder

[{"latitude":48.872438,"longitude":2.29811,"state":"75, Paris, Île-de-France","city":"Paris","zipcode":...}]

My wish is to have all of this concatenated in one JSON that will be "pushed to the database". I tried to apply a merge or even a mergeWith. In vain.

Any help would be greatly appreciated.

Thank You.

Solution

Can you try tap, like this, so instead of subscribing , get using from and then tap both. Apologies if this does not work, it is not tested

export class PointsInterceptor implements NestInterceptor {
  intercept(context: ExecutionContext, next: CallHandler): Observable<any> {
    const monaddress = context.switchToHttp().getRequest().body;
    const geocodeResult = from(geocoder.geocode(monaddress));
    const geoCoder = await lastValueFrom(geocodeResult);

    return next.handle().pipe(
      tap(value => console.log(value)),
      map(value => {
        //1: Returning an object from both next.handle() and geoPremiseToObservable
        return {
          httpResponse: value,
          geoCoder: geoCoder
        };

       //2: Returning an single object by merging the geocoder response with http response
        return {
          ...value,
          geoCoder: geoCoder
        };
      })
    );
  }
}