JSFiddle - React, Tailwind, and code Playground

JavaScript

class A {
  get a() {
    return 1;
  }

  sayHi() {
    console.log(this.a)
  }
}

class B extends A {
  sayHi() {
    super.sayHi();
  };
}
var obj = {
  a: 4
};
let b = new B();
b.sayHi();
// logs 1

b.sayHi.call(obj);
// logs 4

obj.sayHi = b.sayHi;
obj.sayHi();
// logs 4