QCM - Section 4: Callbacks and (Partie 8)

Quiz: QCM - Section 4: Callbacks and (Partie 8)

5 questions | Difficulté: moyen

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Question 1

What is the pattern used in the code example for creating vehicles?

• A. Singleton Pattern
• B. Factory Method Pattern
• C. Prototype Pattern
• D. Abstract Factory Pattern

Voir la réponse

Réponse correcte: D

The pattern used is the Abstract Factory Pattern.

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Question 2

What will be the output of console.log(car === truck) in the code example?

• A. true
• B. false
• C. undefined
• D. null

Voir la réponse

Réponse correcte: C

The objects are created using the Abstract Factory Pattern, but they are not the same instance, so the output will be ‘false’.

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Question 3

What does the code typeof InstallTrigger !== 'undefined' check for in the browser detection method?

• A. Firefox version
• B. Opera version
• C. Safari version
• D. Chrome version

Voir la réponse

Réponse correcte: B

This code checks if Firefox is being used by checking the existence of the InstallTrigger variable.

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Question 4

What does the code Object.prototype.toString.call(window.HTMLElement).indexOf('Constructor') > 0 check for in the browser detection method?

• A. Firefox version
• B. Opera version
• C. Safari version
• D. Edge version

Voir la réponse

Réponse correcte: C

This code checks if the browser is Safari by looking for the presence of the ‘Constructor’ in the toString method of the HTMLElement constructor.

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Question 5

What is the purpose of the !!window.chrome && !!window.chrome.webstore condition in the browser detection method?

• A. Checking if the browser is Chrome
• B. Checking if the browser is Firefox
• C. Checking if the browser is Safari
• D. Checking if the browser supports the web store feature of Chrome

Voir la réponse

Réponse correcte: D

This condition checks if the browser supports the web store feature of Chrome.

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