How do I inject a class rather than an instance of a class?

[RGBboy]

This is a simplified version of what I am trying to do:

export class Factory {

  @Inject(MyClass)
  constructor (MyClass) {
    this.MyClass = MyClass;
  }

  create () {
    return new this.MyClass();
  }

}

export class MyClass {
  ...
}

Is there a way to get DI to pass a class rather than an instance of a class?

[pkozlowski-opensource]

@RGBboy Ha, was bumping into this one as well. What you can do today is to create a factory function that would return a constructor, sth along those lines:

@Provide(MyClass)
function myClassProvider() {
  return MyClass;
}

When you do so MyClass just becomes a token that DI is using to match "a thing" to inject with a provider that provides "the thing". Ah, don't forget to pass this factory function to the Injector, here is a unit tests that illustrates this scenario: https://github.com/angular/di.js/blob/master/test/injector.spec.js#L73

[pkozlowski-opensource]

@vojtajina did you consider adding any sugar annotation to reduce typing in this particular scenario a bit?

[RGBboy]

Ok great, thanks for the tip.

[vojtajina]

I think we should support "pre-bound constructors", see #22 (comment)

What's the point of this? I mean, if it's just a class (without any state), why bother with DI?

[vojtajina]

After reading https://github.com/angular/di.js/pull/20/files#r10274718 I think I can see a use case...

I need to think about this some more. What you are asking for is more less "value" from angular 1.x. Maybe we could solve this with "pre-bound provider" (or class, constructor or whatever we call it). This would be just a special case where nothing is prebound and so you just get the provider.

[pkozlowski-opensource]

@vojtajina yes, exactly, this is like a value from the current AngularJS DI.