Is it possible to reinforce constructor param name/types?

[anthonyma94]

Is it possible to reinforce constructor param name/types?

[jeffijoe]

TL;DR: No, it is not possible with CLASSIC injection; it's somewhat possible with PROXY and createContainer<YourCradleType>()

---

This was a design decision from the start.

The problems I have with Inversify and @inject(UserRepository) are:

• requires referencing the DI library
• requires reflect-metadata

Additionally, interfaces are the most natural way to describe, well, an interface, and from what I can tell, in Inversify you don't get type safety when injecting interfaces (requires @inject(TYPES.UserRepository) where TYPES is a collection of symbols manually maintained. Therefore, the lack of type safety at this level in Awilix was acceptable due to what we gained.

In practice, you will rarely ever encounter type issues that you don't catch as you are writing/copy-pasting code, or with automated tests.

If you really feel that it's worth the trouble (some users do! I personally don't) you can use PROXY injection + a cradle type.

interface Cradle {
  userRepository: UserRepository // or IUserRepository if an interface!
}

const container = createContainer<Cradle>({ injectionMode: InjectionMode.PROXY })

// woah!
class Consumer {
  constructor({ userRepository }: Pick<Cradle, 'userRepository'>) {}
}

// typed!
container.register({ 
  userRepository: asClass(UserRepository),
  consumer: asClass(Consumer)
})

// safe!
container.resolve('consumer')

Mind you, however, that CLASSIC injection is probably the cleanest (no proxy magic) and it is also the most performant after the container is initialized. There is a slight overhead with the proxy (not significant), but worth mentioning.