JS OOP

Question 1

What is a method?

Answer 1

a function which is a property of an object. In JS functions themselves are objects. So a method is actually an object reference to a function.

Question 2

What does a method do?

Answer 2

they are actions that can be performed on objects

Question 3

What is this?

Answer 3

this keyword refers to the object it belongs to. It refers to the global object in a function

Question 4

What does bind do?

Answer 4

bind() method creates a new function when invoked, has the this sets to the provided value. It allows an object to borrow a method from another object without making a copy of that method

Question 5

What is the difference between a function and an object literal?

Answer 5

a function you create an object that can be instantiated into multiple instances, while the literal notation delivers a single object.

Question 6

What is Prototypal Inheritance?

Answer 6

inheritance from other prototypes of Objects

Question 7

What is the Prototypal Chain?

Answer 7

all objects in JS are instances of objects which sits on the top of the prototypal chain

Question 8

In the custom object we created, where did the other __proto__ come from?

Answer 8

from the curly braces

Question 9

Why does JS have prototypal inheritance?

Answer 9

when you create it once, you save memory when you only need to do it once. Basically for the sake of memory

Question 10

What does the new keyword do?

Answer 10

creates an empty object, then sets the constructor object to another object, then it gets passed into the function as this, lastly returns this if the function doesn’t return an object.

Question 11

I could’ve added a method to the constructor function by assigning a method to a property on the this object. Why do we have to add it to the prototype property?

Answer 11

because of inheritance and memory efficiency

Question 12

What is the first thing that happens in a class when it is instantiated with the new keyword?

Answer 12

calls the constructor function

Question 13

Since classes are technically functions as well. Can you name a difference between classes and functions?

Answer 13

classes don’t hoist. functions can hoist

Question 14

What is a static method?

Answer 14

they are not called on instances of the class but instead they’re called on the class itself

Question 15

What is the benefit of instantiating Classes within other classes?

Answer 15

it enables you to group classes that are only used in one place.

Question 16

Why are parent - child relationships important in OOP?

Answer 16

you can reuse functionality common to all the object types rather than having to duplicate it. By having connection with class within another class.

Question 17

What is the basic idea of OOP?

Answer 17

we use objects to model real world things that we want to represent inside our programs or provide a simple way to access functionality that would otherwise be hard. To avoid spaghetti code.

Question 18

Why is it important to assign callback methods to properties in the constructor?

Answer 18

in order to save it. to reference it in the future

Question 19

Why did the maker class require all the parent class info?

Answer 19

the maker is responsible for making the parent class

Question 20

Why did you have to bind this for the replenishfood method?

Answer 20

so that it would work when passed forward to the parent class

Question 21

What decides the order in which JS files must be loaded?

Answer 21

if its calling a data, you have to include it first. If you want to use a tool, it needs to exist already.