JS constructor inheritance, Object.create(), class

class.js

function Person(firstName, lastName) {
	this.firstName = firstName;
	this.lastName = lastName;
}

Person.prototype.greeting = function () {
	return `Hello there ${this.firstName} ${this.lastName}`;
};

const person1 = new Person('John', 'Doe');

console.log(person1.greeting());

// Inheritance ---------------------------------------------

function Customer(firstName, lastName, phone, membership) {
	// Inherit the person prototype methods
	Person.call(this, firstName, lastName);
	this.phone = phone;
	this.membership = membership;
}

// Inherit the person prototype methods
Customer.prototype = Object.create(Person.prototype);
// Make customer.prototype return Customer()
Customer.prototype.constructor = Customer;

const customer1 = new Customer('Tom', 'Smith', '333-333-3333', 'Standard');

console.log(customer1);

Customer.prototype.greeting = function () {
	return `Hello there ${this.firstName} ${this.lastName} welcome to our company`;
};

console.log(customer1.greeting());

// Object.create() ----------------------------------------

const personPrototypes = {
	greeting: function () {
		return `Hello there ${this.firstName} ${this.lastName}`;
	},
	getsMarried: function (newLastName) {
		this.lastName = newLastName;
	}
};

const mary = Object.create(personPrototypes);
mary.firstName = 'Mary';
mary.lastName = 'Williams';
mary.age = 30;

mary.getsMarried('Thompson');
console.log(mary);
console.log(mary.greeting());

// class -------------------------------------------------

class Person {
	constructor(firstName, lastName, dob) {
		this.firstName = firstName;
		this.lastName = lastName;
		this.birthday = new Date(dob);
	}

	greeting() {
		return `Hello there ${this.firstName} ${this.lastName}`;
	}

	// How to calculate age in javascript
	calculateAge() {
		const diff = Date.now() - this.birthday.getTime();
		const ageDate = new Date(diff);
		return Math.abs(ageDate.getUTCFullYear() - 1970);
	}

	getsMarried(newLastName) {
		this.lastName = newLastName;
	}

	static addNumbers(x, y) {
		return x + y;
	}
}

const mary = new Person('Mary', 'Jane', '12-5-1980');
mary.getsMarried('Thompson');

Person.addNumbers(1, 2);

class Customer extends Person {
	constructor(firstName, lastName, phone, membership) {
		super(firstName, lastName);
		this.phone = phone;
		this.membership = membership;
	}
	static getMembershipCost() {
		return 500;
	}
}

const john = new Customer('John', 'Doe', '444-444-4444', 'Standard');
console.log(john);
console.log(john.greeting());
console.log(Customer.getMembershipCost());