Class

Question 1

commas are needed between class methods

TRUE / FALSE

Answer 1

FALSE

Question 2

class User {
  constructor(name) { this.name = name; }
  sayHi() { alert(this.name); }
}

alert(typeof User); //

Answer 2

function

Question 3

class User {
  constructor() {}
}

alert(typeof User);
User(); // returns

Answer 3

Error: Class constructor User cannot be invoked without ‘new’

Question 4

A class definition sets enumerable flag to ________ for all methods in the “prototype”.

Answer 4

false

Question 5

Class methods are non-enumerable.

True / False

Answer 5

true

Question 6

All code inside the class construct is automatically in strict mode.

True / False

Answer 6

True

Question 7

let User = class MyClass {
  sayHi() {
    alert(MyClass); // MyClass is visible only inside the class
  }
};

new User().sayHi(); //

Answer 7

works, shows MyClass definition

Question 8

let User = class MyClass {
  sayHi() {
    alert(MyClass); // MyClass is visible only inside the class
  }
};

alert(MyClass); //

Answer 8

error, MyClass not visible outside of the class

Question 9

MyClass is technically a ___________ (the one that we provide as constructor), while methods, getters and settors are written to MyClass.prototype.

Answer 9

function

Question 10

The _________ keyword is used in class declarations or class expressions to create a class which is a child of another class.

Answer 10

extends

Question 11

The________ keyword is used to access and call functions on an object’s parent.

Answer 11

super

Question 12

to call a parent method using super

Answer 12

super.methons(…)

Question 13

to call a parent constructor (inside our constructor only) using super

Answer 13

super(…)

Question 14

class Animal {

constructor(name) {
this.speed = 0;
this.name = name;
}

run(speed) {
this.speed += speed;
alert(${this.name} runs with speed ${this.speed}.);
}

stop() {
this.speed = 0;
alert(${this.name} stopped.);
}

}

class Rabbit extends Animal {
  hide() {
    alert(`${this.name} hides!`);
  }

  stop() {
    \_\_\_\_\_\_\_\_ // call parent stop
    \_\_\_\_\_\_\_\_\_ // and then hide
  }
}

Answer 14

super. stop();

super. stop();

Question 15

Arrow functions have super

TRUE / FALSE

Answer 15

Arrow functions have no super

Question 16

We can also assign a method to the class function, not to its “prototype”. Such methods are called _______.

Answer 16

static