Add multiple services under the same type and getMany?

[justinmchase]

For example:

const types = {
  IA: Symbol("IA")
};

// Interfaces
interface IA {
  foo(): void;
}

// Implementations
@Service()
class A implements IA {
  public foo(): void {
    console.log("A");
  }
}

@Service()
class B implements IA {
  public foo(): void {
    console.log("B");
  }
}

// Service collection setup.
const serviceCollection = new ServiceCollection();
serviceCollection.pushTransient<IA>(types.IA, A);
serviceCollection.pushTransient<IA>(types.IA, B);

const services = serviceCollection.getMany(types.IA);

[luvies]

I've seen other DI libraries with this and I do quite like it, it's just not been added before since I've not been sure on the best way to go about it. I do quite like using push[Lifetime] instead of just overloading add[Lifetime] (along with getMany instead of just an overloaded get), since it prevents any sort of misuse between single service and multi-service bindings.

I would also like for multi-service bindings to be supported with constructor and property injection. Following the separation between push and add, I think adding @InjectMany instead of overloading @Inject would be ideal. The new decorator could also be the canonical way of using multi-service injection in the constructor, so any parameters that don't have any decorator always use the single-injection mechanism (again, to prevent overloading).

If this seems reasonable I can look at adding this feature soon.