Master.js

//** ABSTRACTION **//

class CoffeeMachine {
 start (){
 // call DB
 //filter value
 return `starting the machine...`
 }
 brewCoffee (){
 //complex Calculation
 return `brewing coffee..`
 }
 pressstartbutton () {
 let msgone = this.start()
 let msgtwo = this.brewCoffee()
 return `${msgone} + ${msgtwo}`
 }
}
let myMachine = new CoffeeMachine();
//console.log(myMachine.start());
//console.log(myMachine.brewCoffee());
console.log(myMachine.pressstartbutton());

// **POLYMORPHISM** //

class Bird {
 fly (){
 return `Birds can fly...`
 }
}
class Penguin{
 fly(){
 return `Penguin can't fly...`
 }
}
let bird = new Bird()
let penguin = new Penguin()
console.log(bird.fly());
console.log(penguin.fly());

//**STATIC METHOD **//

class Calculator {
 static add (a,b){
 return a+b;
 }
}
console.log(Calculator.add(2,3));
//let minicalc = new Calculator()
//console.log(minicalc.add(2,3));