Control Flow and Functions in JavaScript: Interactive Learning Quizzes

Question 1

Which of the following statements correctly defines a **conditional statement** in JavaScript?

Accepted Answer

**if (condition) { // code to be executed }**

Answer

**condition ? true : false**

Answer

**function condition() { // code to be executed }**

Answer

**while (condition) { // code to be executed }**

Question 2

Which of the following options is **NOT** a valid type of **loop** in JavaScript?

Accepted Answer

**for each**

Answer

**while**

Answer

**do while**

Answer

**for**

Question 3

Which statement below is used to **prematurely exit** a loop in JavaScript?

Accepted Answer

**break**

Answer

**continue**

Answer

**exit**

Answer

**stop**

Question 4

What is the **purpose** of a **function** in JavaScript?

Accepted Answer

**To group related code together and perform a specific task**

Answer

**To create new variables**

Answer

**To store data**

Question 5

What is the **difference** between a **function declaration** and a **function expression**?

Accepted Answer

**A declaration hoists the function to the top of the scope, while an expression does not.**

Answer

**A declaration returns a value, while an expression does not.**

Answer

**A declaration can only be called after it is defined, while an expression can be called immediately.**

Question 6

What is the **purpose** of the **'return'** statement in a JavaScript function?

Accepted Answer

**To terminate the execution of the function and optionally return a value.**

Answer

**To pass data to the calling function**

Answer

**To define the input parameters of the function**

Question 7

Which of the following is **NOT** a valid way to **pass arguments** to a function in JavaScript?

Accepted Answer

**By reference**

Answer

**Through the function parameters**

Answer

**By value**

Answer

**Through global variables**

Question 8

What is the **difference** between a **local variable** and a **global variable** in JavaScript?

Accepted Answer

**Local variables are only accessible within the function they are defined in, while global variables are accessible from anywhere in the program.**

Answer

**Local variables are stored in the stack, while global variables are stored in the heap.**

Question 9

Which of the following is **NOT** a **benefit** of using functions?

Accepted Answer

**It makes code harder to read and understand.**

Answer

**It allows for code reuse**

Answer

**It reduces the potential for errors**

Answer

**It improves modularity**

Question 10

Which of the following is used to create reusable code blocks in JavaScript?

Accepted Answer

Functions

Answer

Loops

Answer

Arrays

Answer

Objects

Question 11

Which keyword is used to declare a variable that cannot be reassigned in JavaScript?

Accepted Answer

const

Answer

let

Answer

export

Answer

var

Question 12

Which of the following is a valid syntax to declare an arrow function in JavaScript?

Accepted Answer

const myFunction = () => {}

Answer

() => {}()

Answer

function () {}

Answer

function () => {}()

Question 13

What does the `break` statement do within a loop?

Accepted Answer

Immediately stops the execution of the loop.

Answer

Continues the execution of the loop.

Answer

Pauses the execution of the loop.

Answer

Skips the current iteration of the loop.

Question 14

Which data type in JavaScript is used to represent true or false values?

Accepted Answer

Boolean

Answer

String

Answer

Number

Question 15

Which of the following is NOT a valid JavaScript operator?

Accepted Answer

&&=

Answer

!

Answer

||

Answer

==

Question 16

What is the correct syntax for an if-else statement in JavaScript to check if a variable 'age' is greater than 18?

Accepted Answer

if (age > 18) {  // Code to execute if age is greater than 18  } else {  // Code to execute if age is not greater than 18  }

Answer

if (age > 18) {  // Code to execute if age is greater than 18  } else if (age <= 18) {  // Code to execute if age is not greater than 18  }

Answer

if (age > 18) ... else {  // Code to execute if age is not greater than 18  }

Answer

if age > 18 {  // Code to execute if age is greater than 18  } else {  // Code to execute if age is not greater than 18  }

Question 17

What is the primary purpose of a loop in JavaScript?

Accepted Answer

To execute a block of code repeatedly until a certain condition is met.

Answer

To define a variable and assign it a specific data type.

Answer

To compare two values and return a boolean result.

Answer

To call a function and pass arguments to it.

Question 18

How do you pass arguments to a function in JavaScript?

Accepted Answer

By listing the arguments inside the parentheses when calling the function, separated by commas.

Answer

By assigning the arguments to the function name using the colon operator.

Answer

By using the arrow function syntax with the arguments in parentheses.

Answer

By using the 'pass' keyword followed by the arguments in parentheses.

Question 19

What is the role of the 'return' statement within a JavaScript function?

Accepted Answer

To exit the function and send back a value to where the function was called.

Answer

To invoke another function from within the current function.

Answer

To iterate through elements of an array.

Answer

To declare a variable within the function's scope.

Question 20

What does the '===' operator do in JavaScript?

Accepted Answer

It compares both the value and the data type of two operands for strict equality.

Answer

It compares only the value of two operands, regardless of their data type.

Answer

It assigns the value on the right to the variable on the left.

Question 21

Which of the following correctly creates an empty array named 'myArray' in JavaScript?

Accepted Answer

let myArray = [];

Answer

let myArray = () => { ... };

Answer

let myArray: [];

Answer

let myArray = {...};

Question 22

What is the key difference between a 'for' loop and a 'while' loop in JavaScript?

Accepted Answer

A 'for' loop is typically used when you know the exact number of iterations needed, while a 'while' loop is used when the number of iterations is unknown and depends on a condition.

Answer

A 'for' loop is more efficient than a 'while' loop, regardless of the situation.