Classes & Objects — Series 2

Preview — 3 of 10 questions

What is logged?

javascript

class Circle {
  constructor(radius) {
    this.radius = radius;
  }
  get area() {
    return Math.PI * this.radius ** 2;
  }
}

const c = new Circle(2);
console.log(c.area);
console.log(typeof c.area);

A[Function: area], "function"

B12.566370614359172, "number"

Cundefined, "undefined"

DTypeError: c.area is not a function

What is logged?

javascript

class Counter {
  count = 0;
  increment() {
    this.count += 1;
    return this.count;
  }
}

const c1 = new Counter();
const c2 = new Counter();

console.log(c1.increment());
console.log(c2.count);

A1, 1

B0, 0

Cundefined, undefined

D1, 0

What is logged?

javascript

class Animal {}
class Dog extends Animal {}

const d = new Dog();

console.log(d instanceof Dog);
console.log(d instanceof Animal);
console.log(d instanceof Object);

Atrue, true, true

Btrue, false, true

Ctrue, true, false

Dfalse, true, true

Answer all 10 questions (7 more), see explanations for every answer, and track your score.