JavaScript Most Asked.

🚀 Master Your JavaScript Skills: Essential Interview Questions to Ace Your Next Tech Interview! 💻✨

1. Basics of JavaScript

• What are the different data types in JavaScript?
• What is the difference between var, let, and const?
• Explain hoisting in JavaScript.
• What is the difference between == and ===?
• What are template literals, and how are they used?
• What is null vs undefined in JavaScript?

2. Functions

• What is a higher-order function in JavaScript?
• Explain the difference between function declarations and function expressions.
• What are arrow functions, and how do they differ from regular functions?
• What is a callback function? Can you give an example?
• What are closures in JavaScript? How and why would you use them?

3. Objects and Prototypes

• What is the difference between a method and a function in JavaScript?
• What is the prototype chain in JavaScript? How does inheritance work?
• How would you create an object in JavaScript?
• What is the difference between Object.create() and constructors (new)?

4. Asynchronous JavaScript

• What is the difference between synchronous and asynchronous JavaScript?
• How do setTimeout and setInterval work in JavaScript?
• What are Promises? Can you explain their basic structure?
• How does async and await work in JavaScript? What are their benefits?
• Explain the event loop and how it works in JavaScript.

5. Arrays and Iterables

• How would you iterate over an array in JavaScript? Name different methods.
• What is the difference between map(), forEach(), filter(), and reduce()?
• How would you find duplicate values in an array?
• Explain how array destructuring works.

6. Scope and Context

• What is the difference between local and global scope in JavaScript?
• What is this in JavaScript, and how is it determined?
• How does bind(), call(), and apply() work? What are the differences?

7. Error Handling

• How does JavaScript handle errors? Explain the try, catch, and finally blocks.
• What are custom errors, and how would you create them?

8. JavaScript ES6 and Beyond

• What are the new features introduced in ES6? (Arrow functions, template literals, destructuring, etc.)
• What are default parameters in ES6?
• Explain rest and spread operators in JavaScript.
• What are generators in JavaScript?

9. DOM Manipulation

• What is the DOM, and how do you interact with it using JavaScript?
• How would you select an element by class, ID, or tag using JavaScript?
• What is event delegation in JavaScript, and how does it work?
• How would you attach event listeners to elements?

10. Advanced Concepts

• What is currying in JavaScript?
• What is memoization, and how can it improve performance?
• Explain debouncing and throttling. What are their use cases?
• What are modules in JavaScript, and how do you export and import them?

11. Memory Management and Performance

• How does JavaScript handle memory management?
• What is the difference between stack and heap memory?
• Explain garbage collection in JavaScript.

12. Miscellaneous

• What is strict mode, and how is it used?
• What are service workers, and how do they relate to Progressive Web Apps (PWAs)?
• What is the purpose of use strict?

13. JavaScript Design Patterns

• Can you explain common JavaScript design patterns like Singleton, Factory, and Module patterns?