Classes challenges

gistfile1.txt

'use strict';

// Your tasks:
// 1. Use a constructor function to implement a 'Car'. A car has a 'make' and a
// 'speed' property. The 'speed' property is the current speed of the car in
// km/h
// 2. Implement an 'accelerate' method that will increase the car's speed by 10,
// and log the new speed to the console
// 3. Implement a 'brake' method that will decrease the car's speed by 5, and log
// the new speed to the console
// 4. Create 2 'Car' objects and experiment with calling 'accelerate' and
// 'brake' multiple times on each of them
// Test data:
// § Data car 1: 'BMW' going at 120 km/h
// § Data car 2: 'Mercedes' going at 95 km/h

function challengesTitle(str) {
  console.log(`\n--- ${str} --- \n\n`);
}

challengesTitle('Challenge 1');

const Car = function (make, speed) {
  this.make = make;
  this.speed = speed;
};

Car.prototype.accelerate = function () {
  console.log(`${this.make} is accelerating at ${this.speed + 10} m/hr`);
};

Car.prototype.brake = function () {
  console.log(`${this.make} is de-accelerating at ${this.speed - 5} m/hr`);
};

const mazda = new Car('Mazda', 120);
const ford = new Car('Ford', 95);

mazda.accelerate();
mazda.brake();

ford.accelerate();
ford.brake();

challengesTitle('Challenge 2');

// 1. Re-create Challenge #1, but this time using an ES6 class (call it 'CarCl')
// 2. Add a getter called 'speedUS' which returns the current speed in mi/h (divide
// by 1.6)
// 3. Add a setter called 'speedUS' which sets the current speed in mi/h (but
// converts it to km/h before storing the value, by multiplying the input by 1.6)
// 4. Create a new car and experiment with the 'accelerate' and 'brake'
// methods, and with the getter and setter.
// Test data:
// § Data car 1: 'Ford' going at 120 km/h

class CarCl {
  constructor(make, speed) {
    this.make = make;
    this.speed = speed;
  }
  accelerate() {
    this.speed += 10;
    console.log(`${this.make} is accelerating at ${this.speed} km/hr`);
  }
  brake() {
    this.speed -= 5;
    console.log(`${this.make} is de-accelerating at ${this.speed} km/hr`);
  }

  get speedUS() {
    return this.speed / 1.6;
  }

  set speedUS(speed) {
    this.speed = speed * 1.6;
  }
}

const datsun = new CarCl('Datsun', 120);
console.log(datsun.speedUS);
datsun.accelerate();
datsun.accelerate();
datsun.brake();
datsun.speedUS = 50;
console.log(datsun);

challengesTitle('Challenge 3');

const ElectricCar = function (make, speed, charge) {
  Car.call(this, make, speed);
  this.charge = charge;
};

// link to prototypes
ElectricCar.prototype = Object.create(Car.prototype);

ElectricCar.prototype.chargeBattery = function (chargeTo) {
  this.charge = chargeTo;
};

ElectricCar.prototype.accelerate = function () {
  this.speed += 20;
  this.charge--;
  console.log(
    `${this.make} is going at ${this.speed} km/h, with a charge of ${this.charge}`
  );
};

const tesla = new ElectricCar('Tesla', 120, 23);
tesla.chargeBattery(90);
console.log(tesla);
tesla.brake();
tesla.accelerate();

// 1. Use a constructor function to implement an Electric Car (called 'EV') as a child
// "class" of 'Car'. Besides a make and current speed, the 'EV' also has the
// current battery charge in % ('charge' property)
// 2. Implement a 'chargeBattery' method which takes an argument
// 'chargeTo' and sets the battery charge to 'chargeTo'
// 3. Implement an 'accelerate' method that will increase the car's speed by 20,
// and decrease the charge by 1%. Then log a message like this: 'Tesla going at 140
// km/h, with a charge of 22%'
// 4. Create an electric car object and experiment with calling 'accelerate',
// 'brake' and 'chargeBattery' (charge to 90%). Notice what happens when
// you 'accelerate'! Hint: Review the definiton of polymorphism 😉
// Test data:
// § Data car 1: 'Tesla' going at 120 km/h, with a charge of 23%