Pewarisan / Inheritance

//supperclass

class MailService {

constructor(sender) {

this.sender = sender;

}

//Method yang kemampuannya sama antara kedua subclass biar tidak terjadi duplikasi kode

sendMessage(message, receiver) {

console.log(`${this.sender} sent ${message} to ${receiver}`);

}

}

//subclass

class WhatsAppService extends MailService {

sendBroadcastMessage(message, receivers) {

for (const receiver of receivers) {

this.sendMessage(message, receiver);

}

}

}

//subclass

class EmailService extends MailService {

sendDelayedMessage(message, receiver, delay) {

setTimeout(() => {

this.sendMessage(message, receiver);

}, delay);

}

}

//Lihatlah bahwa didalam subclass WhatsAppService dan EmailService kita tetap memiliki akses terhadap method dari superclass melalui keyword this

//karena subclass mewarisi sifat dari superclass

//Pemanggilan

const whatsapp = new WhatsAppService('+6281234567890'); //+6281234567890 sebagai sender

const email = new EmailService('[email protected]');

whatsapp.sendMessage('Hello', '+6289876543210');

whatsapp.sendBroadcastMessage('Hello', ['+6211111111', '+6233333333']); //dapat mengirimkan 1 pesan ke 2 orang secara bersamaan

//whatsapp.sendDelayedMessage(); akan error

email.sendMessage('Hello', '[email protected]');

email.sendDelayedMessage('Hello', '[email protected]', 3000); //akan delay beberapa detik

//email.sendBroadcastMessage(); akan error