Composition/Inheritance JavaScript

compsition.js

// Part I: objects and composition 

const Person = {
  set givenName(givenName) {
    this._givenName = givenName;
  },
  set familyName(familyName) {
    this._familyName = familyName;
  },
  fullName() {
    return `${this.givenName} ${this.familyName}`;
  },
};

const Customer = Object.assign(
  {}, // create a new object by extending prototype Person
  Person,
  // add score prop for and doubleScore function for customer 
  {
    set score(score) {
      this._score = score;
    },
    doubleScore() {
      return this.score * 2;
    },
  }
);

const Employee = Object.assign(
  {}, // create a new object by extending prototype Person
  Person,
  // add salary prop and bonus function for employee 
  {
    set salary(salary) {
      this._salary = salary;
    },
    bonus() {
      return this.salary * 0.2;
    },
  }
);

// Part II: implemenation 

const john = Object.create(Customer);
john.givenName = 'John';
john.familyName = 'Doe';
john.score = 100;
const jane = Object.create(Customer);
jane.givenName = 'Jane';
jane.familyName = 'Doe';
jane.score = 155;
const jack = Object.create(Employee);
jack.givenName = 'Jack';
jack.familyName = 'Black';
jack.salary = 1000;
const jill = Object.create(Employee);
jill.givenName = 'Jill';
jill.familyName = 'White';
jill.salary = 1200;

console.log('Customer fullName   :', john.fullName());
console.log('Customer doubleScore:', john.doubleScore());

console.log('Customer fullName   :', jane.fullName());
console.log('Customer doubleScore:', jane.doubleScore());

console.log('Employee fullName   :', jack.fullName());
console.log('Employee bonus      :', jack.bonus());

console.log('Employee fullName   :', jill.fullName());
console.log('Employee bonus      :', jill.bonus());
console.log('Check john prototype for Customer', Object.getPrototypeOf(john) === Customer);
console.log('Check john prototype for Employee', Object.getPrototypeOf(john) === Employee);