OOP

Question 1

What is amethod?

Answer 1

A function that is a property of an object

Question 2

How can you tell the difference between a methoddefinitionand a methodcall?

Answer 2

Method definition is a shorter syntax for defining a function property in an object initializer.

Method call has an argument

Question 3

Describe methoddefinitionsyntax (structure).

Answer 3

Var object = {
method() {
return ‘something’
}
};

Question 4

Describe methodcallsyntax (structure).

Answer 4

methodName(argument);

Question 5

How is a method different from any other function?

Answer 5

A method is associated with an object, while a function is not
Usually a method is group with other similar properties

Question 6

What is thedefining characteristicof Object-Oriented Programming?

Answer 6

It stores data in objects to create better structured and reusable code

Question 7

What are the four “principles” of Object-Oriented Programming?

Answer 7

Abstraction, Encapsulation, Inheritance, Polymorphism

Question 8

What is “abstraction”?

Answer 8

The idea of breaking down something that is complex into simpler terms

Question 9

What does API stand for?

Answer 9

Application Programming Interface

Question 10

What is the purpose of an API?

Answer 10

To allow two or more programs to communicate with each other

Question 11

What isthisin JavaScript?

Answer 11

“This” is the object that a method called with

Question 12

What does it mean to say thatthisis an “implicit parameter”?

Answer 12

It is available in the code block even through it was never included in the function’s definition

Question 13

Whenis the value ofthisdetermined in a function;call timeordefinition time?

Answer 13

The value of “this” is determined when the function is called

Question 14

How can you tell what the value ofthiswill be for a particular function or methoddefinition?

Answer 14

You can’t tell?

Question 15

How can you tell what the value ofthisis for a particular function or methodcall?

Answer 15

look at the object name to the left of the dot

Question 16

What kind of inheritance does the JavaScript programming language use?

Answer 16

Prototypal inheritance (objects inherit from other objects)

Question 17

What is a prototype in JavaScript?

Answer 17

an object that contains properties and (predominantly) methods that can be used by other objects.

Question 18

How is it possible to call methods on strings, arrays, and numbers even though those methods don’t actually exist on strings, arrays, and numbers?

Answer 18

The methods are defined on a prototype object and those methods are borrowed as needed

Question 19

If an object does not have it’s own property or method by a given key, where does JavaScript look for it?

Answer 19

In the objects prototype chain
It will go down prototype chain until it runs out of things to look at
If there’s nothing, it returns undefined

Question 20

What does thenewoperator do?

Answer 20

It creates an instance of a user defined object or one of the constructor objects

Question 21

What property of JavaScript functions can store shared behavior for instances created withnew?

Answer 21

AFunctionobject’sprototypeproperty is used when the function is used as a constructor with thenewoperator.