Alternatives in the example code of 1-js/09-classes/07-mixins may be wrong

[AmosChenYQ]

let sayMixin = {
  say(phrase) {
    alert(phrase);
  }
};

let sayHiMixin = {
  __proto__: sayMixin, // (or we could use Object.create to set the prototype here) !!! this may be wrong

  sayHi() {
    // call parent method
    super.say(`Hello ${this.name}`); // (*)
  },
  sayBye() {
    super.say(`Bye ${this.name}`); // (*)
  }
};

class User {
  constructor(name) {
    this.name = name;
  }
}

// copy the methods
Object.assign(User.prototype, sayHiMixin);

// now User can say hi
new User("Dude").sayHi(); // Hello Dude!

Object.create can set proto of sayHiMixin, but its method can be only function properties by

let sayHiMixin = Object.create(sayMixin, {
    sayHi: {
        value: function() {
            super.say(`Hello ${this.name}`);
        },
        enumerable: true
    }
});

or

sayHiMixin.sayHi = function() {
 // ....
}

Calling super later will cause an error becasue both in these way there;s no [[HomeObject]], super keyword unexpected here.

[iliakan]

Indeed. Merged!