Make Components implement an Interface instead of extending VueComponent

With J2CL when extending a class with the @JsType annotation, then the child class must have a constructor annotated with @JsConstructor.

Currently, Components are extending VueComponent (which is a native @JsType), so they would need a @JsConstructor to compile in J2CL. To avoid needing to create this constructor in each Component, I propose to introduce an interface that Components implement instead of extending VueComponent.

This interface would look like this:

public interface IsVueComponent {
   default VueComponent asVue() {
      return Js.cast(this);
   }
}

This would make all Vue.js Components methods (like $emit) or properties (like $el) accessible in Components this way instead of directly on this:

asVue().$emit("my-event");

This also open up the possibility of adding more idiomatic methods as default in this interface to access attributes/elements on the Component.

Even if this is a pretty big breaking change, the migration from Beta 7 should be fairly easy as it would just require replacing all extends VueComponent with implements IsVueComponent.

Feedback on the name of this interface (IsVueComponent) and this idea is welcome!

[slavap]

@adrienbaron vue() is better than asVue()

[slavap]

@adrienbaron Go ahead, I’m quite overloaded today 😦