Welcome to the Functions & Objects section of the JavaScript Interview Questions repository.

This module covers one of the most important areas of JavaScript that is frequently tested in technical interviews. Understanding functions, objects, closures, lexical scope, object manipulation, and modern ES6 features is essential for becoming a confident JavaScript developer.

Whether you are preparing for campus placements, service-based companies, product-based companies, or JavaScript developer interviews, these questions will help strengthen your understanding of JavaScript functions and objects.

After completing this module, you will be able to:

• Understand JavaScript functions and their different types.
• Differentiate between function declarations and function expressions.
• Write and use arrow functions.
• Understand Immediately Invoked Function Expressions (IIFE).
• Work with callback functions and higher-order functions.
• Explain closures and lexical scope.
• Understand the behavior of the this keyword.
• Create and manipulate JavaScript objects.
• Use object destructuring effectively.
• Apply the spread and rest operators.
• Work with default parameters.
• Use optional chaining and nullish coalescing.
• Create and use object methods.
• Understand method chaining.
• Differentiate between object freezing and object sealing.

• What is a function?
• Function expressions
• Arrow functions
• IIFE
• Callback functions
• Higher-order functions
• Closures
• Lexical scope

• The this keyword
• Object literals
• Creating objects
• Object destructuring
• Spread operator
• Rest operator
• Default parameters
• Optional chaining
• Nullish coalescing
• Object methods
• Method chaining
• Object freezing and sealing

This module contains 20 frequently asked JavaScript interview questions.

Before starting this module, you should have a basic understanding of:

• JavaScript Fundamentals
• Variables
• Data Types
• Operators
• Conditional Statements
• Loops

For each interview question:

1. Read the interview question carefully.
2. Understand the answer.
3. Study the explanation.
4. Practice the example program.
5. Verify the output.
6. Review the key points.
7. Read the interview tip.

Following this approach will help you understand concepts more effectively and answer interview questions with confidence.

After completing this module, you will be able to:

• Write clean and reusable JavaScript functions.
• Understand function execution and scope.
• Work confidently with JavaScript objects.
• Use modern ES6 features in real-world applications.
• Solve function- and object-based interview questions.
• Improve problem-solving skills for technical interviews.

• Previous Module: JavaScript Fundamentals (Q1–Q20)
• Current Module: Functions & Objects (Q21–Q40)
• Next Module: Arrays & ES6 (Q41–Q60)

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Functions and objects form the foundation of JavaScript programming. Mastering these concepts is essential for writing efficient, reusable, and maintainable code. This module provides the knowledge and interview preparation needed to confidently answer some of the most commonly asked JavaScript interview questions.

Happy Learning and Keep Coding!