3) JavaScript - Advanced Topics (Checkpoints 18-21)

Question 1

Which of these is an object constructor?

Accepted Answer

function Bunny(type) {
 this.type = type;
}

Answer

var Bunny = {type: ""chocolate""};

Answer

Bunny.create();

Answer

Object.create(Bunny);

Question 2

function Star() { // function body };
var andromeda = new Star();

How might you visually depict the prototype chain of `andromeda`?

Accepted Answer

andromeda --> Star.prototype --> Object.prototype --> null

Answer

andromeda --> Star --> Function.prototype --> Object.prototype --> null

Answer

andromeda --> Star.prototype -> Function.prototype --> Object.prototype --> null

Answer

andromeda --> Star --> Object.prototype --> null

Question 3

var numbers = [4, 84, 9, 7, 33];
numbers.length; // returns 5
numbers.length = 4;

Given the code above, what will `numbers.length` return?

Accepted Answer

4

Answer

5

Answer

undefined

Answer

null

Question 4

x = ["y", "z"];
console.log(typeof x);

What prints to the console?

Accepted Answer

"object"

Answer

"array"

Answer

null

Answer

undefined

Question 5

var myString = "This is a string!";
myString.length;

True or false: In this example, `length` is an own property on `myString`.

Answer

true

Question 6

var protoFrog = { // some properties };
var greenFrog = Object.create(protoFrog);

How might you visually depict the prototype chain of `greenFrog`?

Accepted Answer

greenFrog --> protoFrog --> Object.prototype --> null

Answer

greenFrog --> protoFrog.prototype --> Object.prototype --> null

Answer

greenFrog --> Object.prototype --> null

Answer

none of these

Perguntas do quiz (6)