Quiz 1

Question 1

temporal dead zone

Answer 1

When you try to access a variable before it has been declared/the “area”/time between the start of a scope and when a variable is actually declared

Question 2

What is an object?

Answer 2

An object is a container of properties

Question 3

What are properties and what can they contain?

Answer 3

Properties belong to objects and have names/“key” and values. They can take any values including other objects and functions

Question 4

What is a prototype?

Answer 4

Inherited properties from another object is called a prototype

Question 5

What is the highest level of a prototype

Answer 5

Object.prototype

Question 6

What is the prototype of “hello” and the prototype of that prototype?

Answer 6

1. String.prototype 2. Object.prototype

Question 7

A property is found by first looking if the object itself contains the property then that object’s prototype and so on until……

Answer 7

it reached an object will null as the prototype such as Object.prototype

Question 8

Give an example of two methods that Object.prototype contains

Answer 8

toString and hasOwnProperty

Question 9

Give an example of two object that Object.prototype contains

Answer 9

String.prototype and Array.prototype

Question 10

Object.create

Answer 10

Object.create(otherObject)

Used to create objects with a specified prototype

Question 11

What does using this.object do when using a constructor?

Answer 11

Creates a property name and value for every new object instantiated with the constructor

i.e.

this.names = [‘jane’, ‘mary’]
c = new Name
d = new Name

c.names will = jane
d.names will = mary

Question 12

hasOwnProperty vs this.object

Answer 12

hasOwnProperty can set properties by inheriting, and this.object creates new/original properties

Question 13

Asynchronous programming allows…?

Answer 13

Allows multiple things to run at the same time. Allows part of code to start now, and finish later

Question 14

What is a callback function?

Answer 14

A function that’s passed into another function, that when called will be called with the result

Question 15

What is a higher order function?

Answer 15

A function that takes a function(s) as a parameter, or that returns a function

Question 16

Give a few examples of builtin higher order functions

Answer 16

foreach, map, reduce, filter

Question 17

Why do we use/make higher order functions?

Answer 17

When we would have to do a bunch of extra things that deal with unimportant details. If we want to repeat the implementation/basic idea of a function on different parameters

Question 18

How are classes defined

Answer 18

class Name {
constructor(){}
methodOne(){}
}

Question 19

What is Object.prototype’s prototype

Answer 19

null

Question 20

Objects can be given prototypes in 3 ways:

Answer 20

Object.create, constructor functions, (ES6) classes

Question 21

Define constructor and instance. Write an example block of code

Answer 21

Constructor is a function with the “new” keyword, and creates an object/instances with the defined prototypes.

Instance is an object created by using the “new” keyword and constructors. You can also say instances are the children of constructors.

function ConstructorName(attr){
this.attr = attr
}

const newInstance = new ConstructorName(‘unique_attr’)