Prototypal Inheritance

GitHub Repository Submission

When using GitHub mode, paste your repository URL below and click Save URL to store it. The saved URL will be automatically included with every message you send until you choose to clear it. Learn more

GitHub Repository URL

Saved GitHub URL

Your GitHub repository URL is saved. LSBot will automatically fetch your latest code from this repository for each message. To change the URL, clear it first and save a new one.

This exercise re-examines exercise 3 from the previous chapter. In that exercise, you wrote a class hierarchy to represent vehicles of various types. In this exercise, we'll rewrite that solution using the constructor/prototype pattern.

Using the constructor/prototype pattern, create some types that represent vehicles, including cars, boats, and planes as specific kinds of vehicles. All vehicles should be able to accelerate and decelerate. Cars should be able to honk, boats should be able to drop anchor, and planes should be able to take off and land. Test your code.

Solution

function Vehicle(color, weight) {
  this.color = color;
  this.weight = weight;
}

Vehicle.prototype.accelerate = function() {
  console.log("Accelerate");
};

Vehicle.prototype.decelerate = function() {
  console.log("Decelerate");
};

function Car(color, weight, licenseNumber) {
  Vehicle.call(this, color, weight);
  this.licenseNumber = licenseNumber;
}

Car.prototype = Object.create(Vehicle.prototype);
Car.prototype.constructor = Car;
Car.prototype.honk = function() {
  console.log("Honk");
};

function Boat(color, weight, homePort) {
  Vehicle.call(this, color, weight);
  this.homePort = homePort;
}

Boat.prototype = Object.create(Vehicle.prototype);
Boat.prototype.constructor = Boat;
Boat.prototype.dropAnchor = function() {
  console.log("Drop anchor");
};

function Plane(color, weight, airline) {
  Vehicle.call(this, color, weight);
  this.airline = airline;
}

Plane.prototype = Object.create(Vehicle.prototype);
Plane.prototype.constructor = Plane;
Plane.prototype.takeOff = function() {
  console.log("Take off");
};

Plane.prototype.land = function() {
  console.log("Land");
};

let car = new Car('red', 3300, 'BXY334');
car.accelerate();             // Accelerate
car.honk();                   // Honk
car.decelerate();             // Decelerate
console.log(car.color, car.weight, car.licenseNumber);
// red 3300 BXY334

let boat = new Boat('yellow', 12000, 'Bahamas');
boat.accelerate();            // Accelerate
boat.decelerate();            // Decelerate
boat.dropAnchor();            // Drop anchor
console.log(boat.color, boat.weight, boat.homePort);
// yellow 12000 Bahamas

let plane = new Plane('blue', 83000, 'Southwest');
plane.accelerate();           // Accelerate
plane.takeOff();              // Take off
plane.land();                 // Land
plane.decelerate();           // Decelerate
console.log(plane.color, plane.weight, plane.airline);
// blue 83000 Southwest

LaunchSchool: An online school for Software Engineers

GitHub Repository Submission

Exercise 2

Solution