OOP

Question 1

What is a method?

Answer 1

A method is a function which is a property of an object. There are two kinds of methods: instance methods which are built-in tasks performed by an object instance, or static methods which are tasks that are called directly on an object constructor.

Question 2

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

Answer 2

defining - has a function code block

calling - has arguments

Question 3

Describe method definition syntax (structure).

Answer 3

-property name:
-function definition(parameters)
code block

Question 4

Describe method call syntax (structure).

Answer 4

object.method(arguments)

doggo.bork()

Question 5

How is a method different from any other function?

Answer 5

The difference is that a method is associated with an object, while a function is not.

if there is a dot - method
no dot - function

Question 6

What is the defining characteristic of Object-Oriented Programming?

Answer 6

objects can contain both data (as properties) and behavior (as methods) that work together

Question 7

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

Answer 7

abstraction
encapsulation
inheritance
polymorphism

Question 8

What is “abstraction”?

Answer 8

being able to work with (possibly) complex things in simple ways

Question 9

What does API stand for?

Answer 9

application programming interface

Question 10

What is the purpose of an API?

Answer 10

way for two or more computer programs to communicate with each other

Question 11

What is this in JavaScript?

Answer 11

it’s an implicit parameter,

Question 12

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

Answer 12

meaning that it is available in a function’s code block even though it was never included in the function’s parameter list or declared with var.

Question 13

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

Answer 13

call time

Question 14

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

Answer 14

if only definition - can’t

Question 15

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

Answer 15

Find where the function is called and look for an object to the left of the dot

(if no dot, this = window)

Question 16

What kind of inheritance does the JavaScript programming language use?

Answer 16

prototype based

prototypal

Question 17

What is a prototype in JavaScript?

Answer 17

source for shared behavior/data

sort of like a toolbox with all the tools

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

within the prototype object

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

prototype

Question 20

What does the new operator do?

Answer 20

1. makes a blank javascript object
2. takes value of the prototype property and sets it
3. turns new object into this (in the code block)
   4.

Question 21

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

Answer 21

.prototype

Question 22

What does the instanceof operator do?

Answer 22

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

we are created instances of ‘human’

Question 23

What is a “callback” function?

Answer 23

function you call inside another function

Question 24

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 24

setTimeout()

Question 25

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

Answer 25

setInterval()

Question 26

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

Answer 26

If this parameter is omitted, a value of 0 is used, meaning execute “immediately”, or more accurately, the next event cycle.

Question 27

What do setTimeout() and setInterval() return?

Answer 27

timeoutID / intervalID