Deck 14: Exploring Object-Based Programming

Question 1

The constructor for Object supports methods that are used to retrieve and define properties for any object.

Answer 1

True

Question 2

To create a custom object as an object literal, you apply the create() method.

Answer 2

False

Question 3

A prototype chain is created by defining an object prototype as a constructor function.

Answer 3

False

Question 4

A prototype chain ranges from the base object class in the chain, known as the superclass down to the lower classes or subclasses .

Question 5

One object can be nested within another.

Question 6

A base object is the only object that has a prototype.

Question 7

Using prototypes, any object class inherits the properties and methods from another class.

Question 8

Methods are shared between objects by applying or calling a method from one object for use in another object.

Question 9

The nested function is hidden from other code in the script, making the code contained and easier to manage.

Question 10

To create object classes, you should apply a function known as an object constructor that defines the properties and methods associated with the object type.

Question 11

The showName() method provides another way to create objects that are based on existing prototypes.

Question 12

The biggest advantage of an object created either as an object literal or with the new Object() command is that the object is reusable.

Question 13

for…in loops do not follow a specific order because properties can be listed and read out in any order.

Question 14

One object class can include objects defined in other classes.

Question 15

A prototype chain should be defined in a top-down order.

Question 16

All prototype chains ultimately find their source in the custom object.

Question 17

JavaScript is an object-based programming language that involves working with the properties and methods associated with objects.

Question 18

You can determine whether an object has the property, prop , using the hasOwnProperty(prop) method.

Question 19

Instantiating an object from a constructor function results in efficient use of memory and resources.

Question 20

When an object is instantiated from a constructor function, it copies the properties and methods from the prototype into the new object.

Question 21

. If the constructor function is a machine to create object instances, then the _____ is the blueprint for the objects that are created.

A) method
B) operator
C) prototype
D) command

Question 22

Which of the following commands is used to create a custom object using the new operator?

A) var objName = new Object(); object.property = value; object.method = function() { commands };
B) var objName = value; object.Name = value; object.property = function() { commands };
C) var method = new Object(); object.property = value; object.objName = function() { commands };
D) var objName = Object(); object.Name = Object(); object.method = function() { commands };

Question 23

Identify the method that ensures that the functions defined in one script do not conflict with functions or variables defined in other scripts.

A) Creating object literals
B) Using object constructors
C) Instantiating objects
D) Nesting the functions

Question 24

Identify the correct syntax to add methods to a custom object.

A) var objName = { function: method () { commands } }
B) var objName = { method: function() { commands } }
C) Commands = { method: function() { var objName } }
D) var objName = { function() { method() } }

Question 25

Identify the structure in which any function, including named functions, is nested within another function.

A) function outsideFn() { commands function insideFn() { commands } commands }
B) outsideFn()function { commands function insideFn() { commands } commands }
C) insideFn() function outsideFn() { function insideFn() { commands } commands }
D) function outsideFn() { commands insideFn function () { commands } commands }

Question 26

Identify the expression used to reference a prototype.

A) objInstance.prototype
B) objClass.prototype
C) objName.prototype
D) objMethod.prototype

Question 27

In an object literal, each _____ pair contains a property and property value associated with the object.

A) name:value
B) object:name
C) object:value
D) name:size

Question 28

Which of the following objects is also known as user-defined objects?

A) Native objects
B) Custom objects
C) Host objects
D) Base objects

Question 29

Which of the following methods is applied to define a custom object?

A) sort() method
B) Shuffle() method
C) create() method
D) Console.log() method

Question 30

Refer to the following code snippet and identify the use of the substring() and toLowerCase() methods. function pokerCard(cardSuit, cardRank) { … this.cardImage() = function() { var suitAbbr = this.suit.substring(0, 1).toLowerCase(); return suitAbbr + this.rankValue + ".p ng"; } }

A) To reset the text string in lowercase
B) To extract the last letter of the string in lowercase
C) To extract the first letter of the string in lowercase
D) To set the lowercase as default

Question 31

Which of the following notations is used to write object properties?

A) object(property)
B) object{"property"}
C) object["property"]
D) Object:"property"

Question 32

Which of the following commands is used to add a method to a prototype .

A) objName.prototype.function = method;
B) objName.prototype.method = function;
C) objClass.prototype.method = function;
D) objInstance.prototype.function = method;

Question 33

Which of the following methods is applied to sort any array in random order?

A) sort() method
B) shuffle() method
C) object create() method
D) console.log() method

Question 34

Identify the general syntax of the object literal.

A) var objName = { value1: name1, value2: name2, … };
B) var objName = { name1: value1, name2: objName, … };
C) var objName = { name1: objnName, name2: value2, … };
D) var objName = { name1: value1, name2: value2, … };

Question 35

Identify the use of var objInstance = new objClass(parameters); command.

A) To create instances of an object
B) To define a user-defined object
C) To create a custom object
D) To add methods to a custom object

Question 36

Identify the significance of this keyword in the following constructor function. function objClass(parameters) { this.prop1 = value1; this.prop2 = value2; … this.method1 = function1; this.method2 = function2; … }

A) It refers to the parameters used by the constructor function.
B) It refers to the properties associated with the object class.
C) It refers to any method associated with the object class.
D) It refers to any object instance of the object class.

Question 37

_____ objects are extended by adding new methods to those object's prototypes.

A) Native
B) Custom
C) Host
D) Base

Question 38

Identify the name:value pair that includes a function name and its commands, which is used to add methods to a custom object.

A) var objName = { method: function() { commands } }
B) var objName = { command.function() { method() } }
C) var obj= { function() { commands } }
D) var objName = { function:method() { commands } }

Question 39

Refer to the following code snippet and identify the use of the shift() method in the code provided. pokerCard.prototype.replaceFromDeck = function(pokerDeck) { this.suit = pokerDeck.cards[0].suit; this.rank = pokerDeck.cards[0].rank; this.rankValue = pokerDeck.cards[0].rankValue; pokerDeck.cards.shift(); }

A) To remove the suit, rank, and rankValue from the pokerDeck object
B) To add the suit, rank, and rankValue to the pokerDeck object
C) To add the first card to the cards array in the pokerDeck object
D) To remove the first card from the cards array in the pokerDeck object.

Question 40

Identify the HTML element that enables the disabled objects to appear semi-transparent on the web page.

A) opacity
B) border
C) float
D) background

Question 41

Which of the following object methods returns a text string representation of object using local standards?

A) obj.LocaleString()
B) object.toLocale()
C) object.toLocaleString()
D) obj.toLocaleString()

Question 42

The _____ Object constructor method freezes obj so that it cannot be modified by other code.

A) Object.freeze(obj)
B) Object.isFrozen(obj)
C) obj.freeze(Object)
D) obj.isFrozen(Object)

Question 43

When you create a custom object using an object literal or by applying the new Object() command, you create a subclass of the _____.

A) base object
B) object literal
C) prototype chain
D) object constructor

Question 44

Identify the Object constructor method that references the prototype of the object, obj .

A) Obj.getPrototypeOf
B) Object.getPrototypeOf(obj)
C) (obj).getPrototypeOf
D) getPrototypeOf(object)

Question 45

The _____ object method returns a text string representation of an object.

A) obj.LocaleString()
B) object.toString()
C) object.toLocaleString()
D) obj.String()

Question 46

Which of the following should be used to examine the properties and keys of an object?

A) forEach() loop
B) call() method
C) for…in loop
D) create() method

Question 47

The _____ method is similar to the apply() method except that the argument values are placed in a comma-separated list of values instead of an array.

A) shuffle()
B) sort()
C) call()
D) create()

Question 48

for…in loops do not follow a specific order because they accept properties that can be listed and read out in any order. If order is important, you can use a(n) _____.

A) object literal
B) Array object
C) prototype chain
D) Object constructor

Question 49

JavaScript objects do not support _____ like arrays do.

A) for loops
B) object literals
C) forEach() methods
D) object constructors

Question 50

Identify the apply() method used to borrow a method from one object class.

A) function.apply(thisObj[,argArray])
B) apply.function(thisObj[,Array])
C) function.apply(thisObj[,apply])
D) Apply.function(Obj[,argArray])

Question 51

Identify the advantage of using JavaScript's built-in Array object methods to loop through the contents of an array.

A) It speeds up the efficiency of your code
B) It defines the properties for any object
C) It connects the object name with an object property
D) It helps to nest anonymous functions within event handlers

Question 52

Identify the function of the "Object.keys(obj)" Object constructor method.

A) Defines or modifies the properties for the object, obj
B) Return true if obj is frozen
C) References the prototype of the object, obj
D) Returns an array of the enumerable properties found in obj

Question 53

Which of the following methods is used to determine whether a property is enumerable?

A) prop.propertyIsEnumerable(obj)
B) obj.propertyIsEnumerable(prop)
C) obj.Enumerable(prop)
D) propertyIsEnumerable(prop)

Question 54

Identify the syntax of the call() method.

A) function.call(arg1, arg2, arg3, ...)
B) function.call(thisObj, arg1, arg2, arg3, ...)
C) call.function(thisObj, arg1, arg2, arg3, ...)
D) function.call(Obj1, Obj2,...)

Question 55

Which of the following Object constructor methods defines or modifies the property, prop , for the object, obj ; where descriptor describes the property.

A) obj.defineProperty(object, prop, descriptor)
B) prop.defineProperty(object, descriptor))
C) Object.defineProperty(obj, prop, descriptor)
D) Object.descriptor(obj, property)

Question 56

Identify the first step that is executed when JavaScript encounters code that references an object property or method.

A) Check for the property or method with the object's prototype
B) Continue moving down the chain until the property or method is located or the end of the chain is reached
C) If the prototype is an instance of another object, check for the property or method in that object
D) Check for the property or method within the current object instance

Question 57

A _____ does not follow a specific order because properties can be listed and read out in any order.

A) for…in loop
B) call() method
C) forEach() loop
D) create() method

Question 58

Which of the following Object constructor methods returns true if obj is frozen?

A) Object.freeze(obj)
B) Object.isFrozen(obj)
C) obj.freeze(Object)
D) obj.isFrozen(Object)

Question 59

You should use the _____ method to test whether each item in an array matches a specified condition.

A) apply()
B) every()
C) call()
D) shuffle()

Question 60

You should start at the top and move down to the lower subclasses to define the _____.

A) base object
B) object literal
C) prototype chain
D) object constructor

Question 61

Case-Based Critical Thinking Questions Case 13-2 Michelle has defined a custom object by creating an object literal. She wants to access the properties of the custom object. Which of the following can help Michelle to access the properties of the custom object?

A) for…in loop
B) Dot operator
C) Prototype chain
D) Base object

Question 63

Simon uses the function.apply(thisObj[,argArray] method to call a method from another object class. In this method, argArray is a(n) _____.

A) argument consisting of arrays
B) array of argument values
C) object calling the arguments of an array
D) method of argument values

Question 64

Case-Based Critical Thinking Questions Case 13-1 Kenneth wants to create a custom object for a specific programming task. He has defined the custom object by creating it as an object literal. Kenneth should store the properties of the object within a comma-separated list of _____ pairs enclosed within a set of curly braces.

A) name:value
B) object:name
C) object:value
D) name:size

Question 65

Case-Based Critical Thinking Questions Case 13-3 Thomas wants to create a custom object using the new operator. He applies the following commands: var objName = new Object(); object.property = value; object.method = function() { commands }; What limitation can Thomas face while creating a custom object using the new operator?

A) He cannot use nested functions.
B) He cannot use prototype chains.
C) He cannot reuse the object.
D) He cannot use a for…in loop.

Question 66

Case-Based Critical Thinking Questions Case 13-3 Thomas wants to create a custom object using the new operator. He applies the following commands: var objName = new Object(); object.property = value; object.method = function() { commands }; The new Object() statement is equivalent to a(n) _____.

A) empty object literal
B) prototype chain
C) for…in loop
D) base object

Question 67

Case-Based Critical Thinking Questions Case 13-4 Edward wants to use object-based programming to create objects that belong to a specific type or class with shared properties and methods. Once the constructor function for the object class is defined, instances of the object are created with the _____ command.

A) var objInstance = new objClass(parameters);
B) var objInstance = objClass(obj);
C) objInstance = new objClass(var);
D) var objInstance = objClass

Question 68

Case-Based Critical Thinking Questions Case 13-4 Edward wants to use object-based programming to create objects that belong to a specific type or class with shared properties and methods. A specific object that belongs to a specific object class, created by Edward, can be termed as a(n) _____.

A) loop
B) instance
C) prototype
D) string

Question 71

Explain how an object can be created with the new operator.

Question 72

Explain how you can apply a for…in loop.

Question 73

Write a note on nested functions.

Question 74

Case-Based Critical Thinking Questions Case 13-2 Michelle has defined a custom object by creating an object literal. She wants to access the properties of the custom object. Michelle can also write the properties of the custom object by using the _____.

A) bracket notation
B) constructor functions
C) prototype chain
D) base object

Question 75

Case-Based Critical Thinking Questions Case 13-5 Steve has created a custom object. He wants to use a template for all the properties and methods associated with the object's class. To add a method to a prototype, Steve should apply the _____ command.

A) objName.prototype.function = method;
B) objName.prototype.method = function;
C) objClass.prototype.method = function;
D) objInstance.prototype.method = function;

Question 76

Case-Based Critical Thinking Questions Case 13-5 Steve has created a custom object. He wants to use a template for all the properties and methods associated with the object's class. Which of the following terms corresponds to the template that Steve wants to use?

A) Loop
B) Instance
C) Prototype
D) String

Question 77

Case-Based Critical Thinking Questions Case 13-1 Kenneth wants to create a custom object for a specific programming task. He has defined the custom object by creating it as an object literal. Kenneth can also use a(n) _____ to define the custom object.

A) base object
B) for…in loop
C) prototype chain
D) object constructor