class-proto.js

/**
 * Creating objects with Classes
 * Versus objects with prototypes
 * Since JavaScript is not a Class-based language
 * what is happening behind the class syntax?
 */

let PersonC = class {
  constructor(nm, id) {
    this.name = nm;
    this.id = id;
  }
  getDetails() {
    return `${this.name} :: ${this.id}`;
  }
};
let bob = new PersonC("Bob", 123);
console.log(bob.getDetails(), bob.name);

let EmployeeC = class extends PersonC {
  // EmployeeC prototype links to PersonC prototype
  constructor(nm, id, salary) {
    super(nm, id);
    this.salary = salary;
  }
  employeeInfo() {
    //exist on the prototype of EmployeeC
    return `${this.name} :: ${this.id} :: ${this.salary}`;
  }
};
let noomi = new EmployeeC("Noomi", 456, 8500000);
console.log(noomi.employeeInfo());

///////////////////////////////////////////////

let PersonP = function(nm, id) {
  this.name = nm;
  this.id = id;
};
PersonP.prototype.getDetails = function() {
  return `${this.name} :: ${this.id}`;
};
let fred = new PersonP("Fred", 321);
console.log(fred.getDetails(), fred.name);

let EmployeeP = function(nm, id, salary) {
  PersonP.call(this, nm, id);
  this.salary = salary;
};
Object.setPrototypeOf(EmployeeP.prototype, PersonP.prototype); //extends NOTE: THIS LINE WAS CHANGED
EmployeeP.prototype.employeeInfo = function() {
  return `${this.name} :: ${this.id} :: ${this.salary}`;
};
let mary = new EmployeeP("Mary", 654, 65000);
console.log(mary.employeeInfo());

I think we also need to add Object.setPrototypeOf(EmployeeP, PersonP) to address static class method prototype inheritance