How to force all parents of a component to implement an interface

app.component.html

<app-child-component></app-child-component>

app.component.ts

import { Component, OnInit } from "@angular/core";
import { TestInterface } from "./test-interface";

@Component({
  selector: "app-root",
  templateUrl: "./app.component.html",
  styleUrls: ["./app.component.scss"]
})
export class AppComponent implements OnInit, TestInterface {
  title = "app";
  isAuth = false;

  constructor() {
    setTimeout(() => {
      this.isAuth = true;
    }, 4000);
  }

  ngOnInit() {}

  // if this method is not present, an exception will be thrown
  testMethod() {
    console.log('test method')
  }
}

child.component.ts

import { Component, OnInit, Host } from "@angular/core";
import { AppComponent } from "../app.component";
import { TestInterface } from "../test-interface";

const TestInterface = {
  // list all the property and methods of the TestInterface type
  // as the type itself is not iterable
  testMethod() {}
}

@Component({
  selector: "app-child-component",
  templateUrl: "./child-component.component.html",
  styleUrls: ["./child-component.component.scss"]
})
export class ChildComponentComponent implements OnInit {
  constructor(@Host() host: AppComponent) {
    // makes sure the parent implements the interface
    Object.keys(TestInterface).forEach(method => {
      if (!Object.getPrototypeOf(host).hasOwnProperty(method)) {
        throw `The class ${Object.getPrototypeOf(host).constructor.name} must implements the method ${method}`;
      }
    })
  }

  ngOnInit() {}
}

test-interface.ts

export interface TestInterface {
    testMethod();
}