class Vehicle {

constructor(name, speed, cost) {

this.name = name;

this.speed = speed;

this.cost = cost;

}

start() {

console.log('Starting vehicle, ' + this.name + ' at ' + this.speed + 'km/h');

}

buy() {

console.log('Buying for ' + this.cost);

}

}

const vehicle = new Vehicle('bicycle', 15, 100);

vehicle.start();

vehicle.buy();

class Car extends Vehicle {

constructor(name, speed, cost, tankSize) {

super(name, speed, cost);

this.tankSize = tankSize;

}

start() {

console.log('Driving car, at ' + this.speed + 'km/h');

}

}

class Plane extends Vehicle {

start() {

console.log('Flying plane, at ' + this.speed + 'km/h');

}

}

class Rocket extends Vehicle {

start() {

console.log('Flying rocket to the moon, at ' + this.speed + 'km/h');

}

}

const car = new Car('Toyota Corolla', 120, 5000);

const plane = new Plane('Boeing 737', 1000, 26000000);

const rocket = new Rocket('Saturn V', 9920, 6000000000);

car.start();

plane.start();

rocket.start();

const car2 = new Car('Toyota Corolla 2', 120, 5000, 2000);

console.log(car2.tankSize); // 2000