Create

• Literal

  const p1 = {
      name: "John"
  };

• Object.create, creates a new object with its prototype set to the given object

  const p1 = {
      name: "John"
  };
  
  const p2 = Object.create(p1);
  
  p1.name; // "John"
  p2.name; // "John"
  
  p1.hasOwnProperty('name'); // true
  p2.hasOwnProperty('name'); // false

• Constructor

  1. A new object is created with its prototype set to the constructor’s prototype

  2. The constructor is then called with its this context bound to that new object

     function Person(name) {
         this.name = name;
     }
     
     const p1 = new Person('John');
     // same as
     // Object.create(Person.prototype)

Encapsulation

• es6+

  class Person {
    constructor(name) {
      this.name = name;
    }
  
    greet() {
      console.log(`Hello, my name is ${this.name}.`);
    }
  }
  
  const john = new Person('John');
  john.greet(); // Hello, my name is John.

• pre-es6

  function Person(name) {
    this.name = name;
  }
  Person.prototype.greet = function() {
    console.log(`Hello, my name is ${this.name}.`);
  };
  
  const john = new Person('John');
  
  john.greet(); // Hello, my name is John

Inheritance

• es6+

  class Employee extends Person {
    constructor(name, job, employer) {
      super(name);
  
      this.job = job;
      this.employer = employer;
    }
  
    greet() {
      super.greet();
      console.log(`I am a ${this.job} at ${this.employer}.`);
    }
  }
  
  const bill = new Employee('Bill', 'cashier', 'Coles');
  
  bill.greet();
  // Hello, my name is Bill.
  // I am a cashier at Coles.

• pre-es6

  function Employee(name, job, employer) {
    Person.call(this, name);
  
    this.job = job;
    this.employer = employer;
  }
  Employee.prototype = Object.create(Person.prototype);
  Employee.prototype.constructor = Employee;
  
  Employee.prototype.greet = function() {
    Person.prototype.greet.call(this);
    console.log(`I am a ${this.job} at ${this.employer}.`);
  };
  
  const bill = new Employee('Bill', 'cashier', 'Coles');
  
  bill.greet();
  // Hello, my name is Bill.
  // I am a cashier at Coles.