Question 1

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

Accepted Answer

The prototype is the blueprint for objects that are created by the constructor function. It contains all the properties and methods that will be available to instances of the object. The prototype is like a template for objects, defining what they will look like and how they will behave.

Question 2

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

Accepted Answer

Option A is correct because it uses the new operator to create a new object and then sets its properties and methods using dot notation. Option B sets the object's properties but does not use the new operator to create a new object. Option C sets a new method object but does not set any properties or create a new object. Option D is incorrect because it tries to call the Object constructor like a function, which will cause an error.

Question 3

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

Accepted Answer

Nesting the functions in a closure ensures that the variables and functions defined in the outer function are not accessible outside of it, thus avoiding conflicts with variables and functions defined in other scripts.

Question 4

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

Accepted Answer

Option B is the correct syntax to add methods to a custom object. It follows the format of methodName: function() { commands } where methodName is the name of the method and commands are the actions to be performed by the method. Options A, C, and D are incorrect syntax for adding methods to a custom object.

Question 5

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

Accepted Answer

The structure in which any function, including named functions, is nested within another function is by defining the outer function first, followed by defining the inner function inside the outer function, as shown in choice A.

Question 6

Identify the expression used to reference a prototype.

Accepted Answer

The answer of Identify the expression used to reference a...

Question 7

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

Accepted Answer

In an object literal, each key-value pair contains a property and property value associated with the object. The format for this key-value pair is "name: value", where the name represents the property and the value represents the value associated with that property for the object.

Question 8

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

Accepted Answer

Custom objects are objects that are created by users themselves, hence they are also known as user-defined objects. Native objects are objects that are built-in to the programming language, host objects are objects provided by the environment in which the code is run, and base objects refer to the basic objects that all other objects inherit from.

Question 9

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

Accepted Answer

To define a custom object, the create() method is commonly used in JavaScript. This method allows us to create a new object with a specified prototype object and properties. The sort() method is used to sort arrays and shuffle() is used to randomly shuffle the elements of an array. The Console.log() method is used for printing messages to the console for debugging purposes.

Question 10

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"; } }

Accepted Answer

The substring() method is used to extract a portion of a string based on the specified indexes. In this code, the substring() method is used to extract the first character of the cardSuit string. The toLowerCase() method is used to convert the extracted character to lowercase before returning it. Therefore, the correct choice is C - to extract the first letter of the string in lowercase.

Question 11

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

Accepted Answer

Object properties are written using square brackets notation with the property name in quotes. Therefore, option C is the correct answer.

Question 12

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

Accepted Answer

The correct syntax to add a method to a prototype is objName.prototype.method = function. Option A and D are incorrect because they use "function" instead of "method". Option C is incorrect because it uses "objClass" instead of "objName".

Question 13

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

Accepted Answer

The shuffle() method is specifically designed to sort an array in random order. The sort() method sorts the array in ascending order by default, and the object create() method and console.log() method do not have any functionality related to sorting arrays.

Question 14

Identify the general syntax of the object literal.

Accepted Answer

The general syntax of the object literal is to define the object with curly braces and list the properties and their values in the format of name: value. Therefore, option D is the correct syntax for object literal as it follows this format. Option A, B, and C have incorrect formatting or reference undefined variables.

Question 15

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

Accepted Answer

The command "var objInstance = new objClass(parameters);" is used to create instances of an object. It creates a new object based on the parameters passed and assigns it to a variable, which can be used to access the object's properties and methods.

Question 16

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; … }

Accepted Answer

In a constructor function, "this" refers to the specific instance of the object being created, allowing properties and methods to be assigned to that instance.

Question 17

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

Accepted Answer

Native objects in JavaScript can be extended by adding new methods to their prototypes.

Question 18

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

Accepted Answer

The name:value pair that includes a function name and its commands, which is used to add methods to a custom object is written as "method:function(){commands}". Option A matches this syntax.

Question 19

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(); }

Accepted Answer

The shift() method is used to remove the first card from the cards array in the pokerDeck object. This card is then assigned to the properties suit, rank, and rankValue of the pokerCard object calling the replaceFromDeck() method.

Question 20

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

Accepted Answer

The opacity property in CSS can be used to control the transparency of an HTML element. By setting the opacity of a disabled object, it can appear semi-transparent on the web page. This is a commonly used technique to visually indicate that an object is disabled and cannot be interacted with.

Quiz 14: Exploring Object-Based Programming