JavaScript Basics Quiz

What is the purpose of the 'let' keyword in JavaScript?

• To declare a variable that is block scoped

• To declare a variable that is globally scoped

• To declare a constant variable

• To declare a variable that can be re-assigned

Which of the following is NOT a primitive data type in JavaScript?

• String

• Object

• Number

• Boolean

What does the 'return' statement do in a function?

• Invokes another function

• Declares a variable

• Returns a value to the caller

• Ends the function execution

What is the result of the expression '2 + '7' in JavaScript?

• 27

• Undefined

• 9

• Error

Which of the following statements is true about the 'this' keyword?

• It always refers to the global object

• It is always undefined

• It refers to the object that is currently executing the function

• It cannot be used in arrow functions

What is a promise in JavaScript?

• A way to handle synchronous tasks

• A method to create variables

• An object that represents the eventual completion of an asynchronous operation

• A function that returns a value immediately

Which of the following is a method to create a new element in the DOM?

• document.getElementById()

• document.removeChild()

• document.createElement()

• document.querySelector()

What does the 'typeof' operator do?

• Checks the equality of two values

• Returns the type of a variable

• Declares a new variable

• Converts a variable to a string

Which of the following is a valid way to declare a function in JavaScript?

• function myFunction() {}

• var myFunction = function() {}

• const myFunction = () => {}

• All of the above

What is the purpose of the 'break' statement in a switch case?

• To exit the loop

• To declare a variable

• To terminate the switch statement

• To skip the current iteration