JavaScript MCQs with answers Page - 139

Here, you will find a collection of MCQ questions on JavaScript. Go through these questions to enhance your preparation for upcoming examinations and interviews.

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Q. Which method is used to handle a resolved Promise?

  • (A) then()
  • (B) catch()
  • (C) resolve()
  • (D) finally()

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Q. Which method is used to handle errors in Promises?

  • (A) catch()
  • (B) then()
  • (C) error()
  • (D) fail()

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Q. What is the purpose of async keyword in JavaScript?

  • (A) To define a function that returns a Promise
  • (B) To pause code execution
  • (C) To define synchronous code
  • (D) To create event loops

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Q. What is the purpose of the await keyword?

  • (A) To wait for a Promise to resolve
  • (B) To block the main thread
  • (C) To delay function execution
  • (D) To create a loop

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Q. Which JavaScript feature allows function to access variables from an outer scope?

  • (A) Closure
  • (B) Scope chain
  • (C) Callback
  • (D) Hoisting

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Q. Which keyword is used to define a class in JavaScript?

  • (A) class
  • (B) object
  • (C) structure
  • (D) function

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Q. How do you create an instance of a class?

  • (A) new ClassName()
  • (B) create ClassName()
  • (C) object ClassName()
  • (D) instanceof ClassName()

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Q. Which method is automatically called when a new object is created?

  • (A) constructor
  • (B) init
  • (C) create
  • (D) build

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Q. What is lexical scope?

  • (A) Scope determined at compile time based on code structure
  • (B) Scope determined at runtime
  • (C) Scope of a function inside a loop
  • (D) Scope within a class

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Q. What will be the output of: typeof Promise?

  • (A) function
  • (B) object
  • (C) undefined
  • (D) promise

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