Object Oriented Programming

Question 1

What is a method?

Answer 1

Value of property of an object that is a function

Question 2

How can you tell the difference between a method definition and a method call?

Answer 2

method definition has the function keyword and codeblock is in the object literal while method call has parenthesis attached at the end

Question 3

Describe method definition syntax (structure).

Answer 3

property name then colon then function definition

Question 4

Describe method call syntax (structure).

Answer 4

object dot notation property then parenthesis

object.property()

Question 5

How is a method different from any other function?

Answer 5

is within an object

Question 6

What is the defining characteristic of Object-Oriented Programming?

Answer 6

based around objects that have data and behavior

Question 7

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

Answer 7

abstraction, encapsulation, inheritance, polymorphism

Question 8

What is “abstraction”?

Answer 8

Simplifying a complex method such as turning on/off a lightbulb when in reality it is closing and opening circuits of electricity that give volts to a lightbulb source

Question 9

What does API stand for?

Answer 9

Application program interface

Question 10

What is the purpose of an API?

Answer 10

communication method between softwares.

Question 11

What is this in JavaScript?

Answer 11

refers to the obj

Question 12

What does it mean to say that this is an “implicit parameter”?

Answer 12

it means that the parameter is not given but it is not given

Question 13

When is the value of this determined in a function; call time or definition time?

Answer 13

call time

Question 14

What does this refer to in the following code snippet? 
var character = {
  firstName: 'Mario',
  greet: function () {
    var message = 'It\'s-a-me, ' + this.firstName + '!';
    console.log(message);
  }
};

Answer 14

this is undefined until called

Question 15

How can you tell what the value of this will be for a particular function or method definition?

Answer 15

no way to know what this

is when a function is called

Question 16

How can you tell what the value of this is for a particular function or method call?

Answer 16

check the object left of the call

Question 17

What kind of inheritance does the JavaScript programming language use?

Answer 17

prototype intheritances

Question 18

What is a prototype in JavaScript?

Answer 18

properties or methods that can be called upon by other

Question 19

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

Answer 19

inheritance, prototype

Question 20

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

Answer 20

at the next parent prototype, until one is found

Question 21

What does the new operator do?

Answer 21

It creates an instance of a user-defined object type

new constructor [([ arguments] )]

Question 22

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

Answer 22

prototype property

Question 23

What does the instance of operator do?

Answer 23

tests to see if the prototype property of a constructor appears anywhere in the prototype chain of an object. Return value is a boolean.

Question 24

What is a “callback” function?

Answer 24

function called within an argument

Question 25

Besides adding an event listener callback function to an element or the document, what is one way to delay the execution of a JavaScript function until some point in the future?

Answer 25

set interval or settimeout

Question 26

How can you set up a function to be called repeatedly without using a loop?

Answer 26

setinterval

Question 27

What is the default time delay if you omit the delay parameter from setTimeout() or setInterval()?

Answer 27

0 or immediately

Question 28

What do setTimeout() and setInterval() return?

Answer 28

TimeoutID