inherit two component in angular with different constructor

Question

This is slightly similar to extending 2 class in typescript, but although I managed to do it in typescript, I can't find a correct way in angular.

I have an angular 7 app with 1 component, a service and a generic class.

Exactly like this Stackblitz

I would like to make a component that inherit from my class, AND my other component

here is my class =>

export class MyClass1<T,O> {
  propertyClass1 = "MyClass1"
  constructor() {
  }

  init(value:string){
    this.propertyClass1 = value;
  }
  sayHelloClass(value:string){console.log('class say'+ value)}
}

here my component =>

export class MyCom1Component implements OnInit {
  propertyComp1 = "MyCom1"
  constructor(private service1:Service1Service) {
      this.propertyComp1 = service1.getProp();
   }

  ngOnInit() {
  }

  sayHelloComponent(value:string){console.log('component say'+ value)}
}

I would like that my child extends booth, so that I am able to do

  ngOnInit() {
    this.sayHelloClass(this.propertyClass1); // class say MyClass1
    this.init("hoohoho");
    this.sayHelloClass(this.propertyClass1); // class say hoohoho


    this.sayHelloComponent(this.propertyComp1); // component say MyCom1
  }

what I tried is this =>

const addMyClassOneInheritance = <T extends new(...args: any[]) => any>(MyCom1Component: T) => {
  return class extends MyCom1Component {
        constructor(...args: any[]) {
            super(...args);
        }
  };
};
const MyMergedClass = addMyClassOneInheritance(MyClass1);
export class ChildComponent extends MyMergedClass<string,number> {
ngOnInit(){
   this.sayHelloClass(this.propertyClass1); // compile ok, execute give a value
   this.sayHelloComponent(this.propertyComp1); // compile ok, execute "can't find sayHelloComponent
}

}

the compiler give no error, but my component methods are not inherited

Answer 1

I would suggest a different approach. Make the class available to DI by annotating it with @Injectable

Then extend your parent component as usual: ChildComponent extend MyCom1Component and inject your MyClass1 using the constructor of ChildComponent Finally call the parent's constructor with the instance of the class you just injected.

constructor(public myclass1: MyClass1) {
    super(myclass1);
  }