How to use the principle of polymorphism?

Question

OOP

There is a class and a service:

interface Search {
    search(): Observable<any>;
}

class CloudService implements Search {
    search(): Observable<any> {
        return of([1,2,3]).pipe(delay(3000));
    }
}

class SearchByAddressParcel implements Search {
    constructor(private CloudService: CloudService) {}

    search() {
        this.CloudService.search().subscribe((response) => {
          console.log(response);
        });
    }
}

Both implement the interface. interface Search {}

The problem is that SearchByAddressParcelthe search method of the class must return void, because the subscription occurs inside the method.

Tomorrow I want a new implementation: c lass SearchByAddressNew {}which should also have a search method and call the service internally.

Then make new SearchByAddressParcel().search()a substitution:new SearchByAddressNew().search();

Answer 1

You can implement a generic :thinking
Either
search(): Observable<any> | void

interface Search<T> {
    search(): T
}

class CloudService implements Search<Observable<any>> {
    search() {
        return of([1,2,3]).pipe(delay(3000));
    }
}

class SearchByAddressParcel implements Search<void> {
    constructor(private CloudService: CloudService) {}

    search() {
        this.CloudService.search().subscribe((response) => {
          console.log(response);
        });
    }
}