Proposal: Track instance registrations separate from factory registrations

[dgeb]

In a Registry, both factories and instances can be registered via register, unregistered via unregister, and accessed via registration.

@krisselden and I discussed the benefits of separating the interfaces to register factories and instances. This change will provide stronger typing for storing and accessing factories and instances.

This would entail the following changes:

• Change Registry#register to accept a more strongly typed FactoryDefinition<any>
• Introduce the following methods to Registry:
  • registerInstance(specifier: string, instance: any): void
  • unregisterInstance(specifier: string): void
  • registeredInstance(specifier: string): any
• In Container#lookup, check the registry's registeredInstance as a first step and return an instance if found.

[dgeb]

I just tweaked the description of this issue, which originally mentioned a simplification for registration options. However, I realized that this was an oversimplification since we still need to register options (like singleton: false) by type.