JavaScript Interview Question: 3 Ways to Remove Duplicates

In the world of tech interviews, JavaScript questions often come up, and knowing how to navigate them can really set you apart. Here are 10 questions you might encounter: 1. What’s the difference between `==` and `===`? 2. Can you explain event delegation? 3. What are closures, and can you give an example? 4. How does the `this` keyword work in JavaScript? 5. What is a promise, and how do you use it? 6. Can you explain asynchronous programming in JavaScript? 7. What’s the purpose of `bind()`, `call()`, and `apply()`? 8. How do you handle errors in JavaScript? 9. What are arrow functions, and how do they differ from regular functions? 10. Can you explain the concept of hoisting? Practice answering these with real-world examples, and you'll be in great shape! #JavaScript #TechInterviews #Coding #WebDevelopment #ProgrammingTips

JavaScript interviews can look simple on the surface, but the real challenge lies in the tricky concepts that test your depth of understanding. Things like: 👉 Why does hoisting behave differently with var, let, and const? 👉 How do closures actually work under the hood? 👉 What really happens inside the event loop? 👉 Why does this change based on how a function is called? 👉 When do call, apply, and bind come into play? 👉 How does JavaScript handle async operations behind the scenes? These aren’t just interview questions — they shape how you write clean, predictable, and efficient code. The best way to master JavaScript is simple: 💡 Read the concept 💡 Predict the output 💡 Break the code 💡 Build small real-world examples Because the moment you can explain why something works the way it does, you’ve already moved from being a coder to a true developer. Keep practicing. Keep questioning. Keep improving. 🚀 #JavaScript #JSInterview #CodingInterview #FrontendDevelopment #WebDevelopment #Programming #LearnToCode #TechCareer #SoftwareEngineering #CodingJourney #DeveloperMindset

JavaScript interview questions I see being asked again and again Although these are basics, they are often overlooked while preparing for more complex topics. These are some of the most commonly asked JavaScript questions across interviews, especially when the focus is on fundamentals and real-world understanding. 1. What is the event loop in JavaScript? 2. What is the difference between "var", "let", and "const"? 3. What is closure and how is it used? 4. What is hoisting in JavaScript? 5. What is the difference between "==" and "==="? 6. What are promises and how do they work? 7. What is the difference between synchronous and asynchronous code? 8. What is "this" in JavaScript and how does it behave? 9. What is the difference between "map", "filter", and "reduce"? 10. What is prototypal inheritance? 11. What are higher-order functions? 12. What is debouncing and throttling? 13. What is the difference between "null" and "undefined"? 14. What is the difference between "call", "apply", and "bind"? 15. What is a polyfill? Can you write a polyfill for "bind"? 16. What is the difference between shallow copy and deep copy? 17. What is event delegation? 18. How does "setTimeout" work under the hood? 19. What is the difference between "setTimeout" and "setImmediate"? 20. What are microtasks and macrotasks? 21. What is currying in JavaScript? 22. What is memoization? 23. What is the difference between "Object.freeze" and "Object.seal"? 24. How does garbage collection work in JavaScript? Strong fundamentals in JavaScript often make a noticeable difference in how you approach real-world problems. Which of these do you find most interesting or tricky? #javaScript #webdevelopment #programming #softwareengineering #InterviewPrep #interview

JavaScript interview questions I see being asked again and again Although these are basics, they are often overlooked while preparing for more complex topics. These are some of the most commonly asked JavaScript questions across interviews, especially when the focus is on fundamentals and real-world understanding. 1. What is the event loop in JavaScript? 2. What is the difference between "var", "let", and "const"? 3. What is closure and how is it used? 4. What is hoisting in JavaScript? 5. What is the difference between "==" and "==="? 6. What are promises and how do they work? 7. What is the difference between synchronous and asynchronous code? 8. What is "this" in JavaScript and how does it behave? 9. What is the difference between "map", "filter", and "reduce"? 10. What is prototypal inheritance? 11. What are higher-order functions? 12. What is debouncing and throttling? 13. What is the difference between "null" and "undefined"? 14. What is the difference between "call", "apply", and "bind"? 15. What is a polyfill? Can you write a polyfill for "bind"? 16. What is the difference between shallow copy and deep copy? 17. What is event delegation? 18. How does "setTimeout" work under the hood? 19. What is the difference between "setTimeout" and "setImmediate"? 20. What are microtasks and macrotasks? 21. What is currying in JavaScript? 22. What is memoization? 23. What is the difference between "Object.freeze" and "Object.seal"? 24. How does garbage collection work in JavaScript? Strong fundamentals in JavaScript often make a noticeable difference in how you approach real-world problems. Which of these do you find most interesting or tricky? #javaScript #webdevelopment #programming #softwareengineering #InterviewPrep #interview

🚨 90% of Developers FAIL JavaScript Interviews… Not because they don’t code — but because they don’t revise SMART. You might know JavaScript… But can you revise everything in just 2 minutes? Most can’t. That’s why they struggle. ⚡ So I created a Quick Revision JavaScript PDF (2-Minute Read) Perfect before: ✔ Interviews ✔ Tests ✔ Practice sessions Inside this PDF: 🔥 Closures 🔥 Promises & Async/Await 🔥 Event Loop 🔥 Hoisting 🔥 Arrow Functions 🔥 Destructuring 🔥 Spread & Rest 🔥 map(), filter(), reduce() 🔥 call, apply, bind 💡 Just 2 minutes = Clear concepts + Better confidence 📩 Want the PDF? 👉 First Follow me 👉 Then comment “JS” 👉 I’ll send you the notes PDF #javascript #webdevelopment #mernstack #frontenddeveloper #codinginterview #learnjavascript #developers #programming

🚨 90% of Developers FAIL JavaScript Interviews… Not because they don’t code — but because they don’t revise SMART. You might know JavaScript… But can you revise everything in just 2 minutes? Most can’t. That’s why they struggle. ⚡ So I created a Quick Revision JavaScript PDF (2-Minute Read) Perfect before: ✔ Interviews ✔ Tests ✔ Practice sessions Inside this PDF: 🔥 Closures 🔥 Promises & Async/Await 🔥 Event Loop 🔥 Hoisting 🔥 Arrow Functions 🔥 Destructuring 🔥 Spread & Rest 🔥 map(), filter(), reduce() 🔥 call, apply, bind 💡 Just 2 minutes = Clear concepts + Better confidence 📩 Want the PDF? 👉 First Follow me 👉 Then comment “JS” 👉 I’ll send you the notes PDF #javascript #webdevelopment #mernstack #frontenddeveloper #codinginterview #learnjavascript #developers #programming

If you're preparing for JavaScript interviews, focus on these 5 core areas 👇 🧠 Core Concepts -Event Loop -Hoisting -Closures -this keyword ⚙️ Variables & Types -var vs let vs const -null vs undefined -== vs === 🔁 Functional Programming -map / filter / reduce -Higher-order functions -Currying & Memoization ⏱ Async JavaScript -Promises -setTimeout internals -Microtask vs Macrotask 🏗 Object & Memory -Prototypal inheritance -Shallow vs Deep copy -Garbage collection 💡 Master these, and 80% of interviews become easier. Which topic do you struggle with the most? #javaScript #webdevelopment #programming #softwareengineering #InterviewPreparation

You don’t fail interviews because you’re bad at coding— You fail because you ignored these 10 JS fundamentals.✍️ You don’t need to know everything. You just need to understand these well enough to explain simply. Because in interviews: - Clarity > Complexity - Fundamentals > Fancy projects Here's top 10 JavaScript fundamentals you must master before the interview. 🔖 Save this post & find the list below Follow me: - Parthib M. 🐺 to explore more updates on Web Development. credit : Rutu Koladiya #javascript #webdevelopment #frontenddeveloper #coding #programming #beginners #softwaredeveloper #interviewtips #100DaysOfCode

🚀 Crack your Frontend Interview like a Pro! Most asked questions from HTML, CSS, JavaScript & React — all in one place 📘💻 Perfect for beginners to advanced devs who want to level up their skills and land their dream job 💼✨ Don’t just prepare… prepare smart! 🔥 #FrontendDeveloper #WebDevelopment #ReactJS #JavaScript #HTML #CSS #CodingLife #DeveloperLife #TechInterview #InterviewPrep #LearnToCode #FullStackDeveloper #Programming #CareerGrowth #JobReady

🚀 Day 6 – Crack Interviews Series 🔹 Topic: What is Debouncing in JavaScript? Debouncing is a technique to delay a function execution until a certain time has passed since the last event. 👉 Useful when events fire frequently (like typing, scrolling). 💡 Real Example: function debounce(fn, delay) { let timer; return function (...args) { clearTimeout(timer); timer = setTimeout(() => { fn.apply(this, args); }, delay); }; } const search = debounce((text) => { console.log("Searching:", text); }, 500); 🎯 Interview Question: Where is debouncing used? 👉 Answer: - Search input (API calls) - Window resize events - Auto-save features 💼 Pro Tip: Debouncing improves performance by reducing unnecessary function calls. 👇 Have you implemented debounce in your projects? 👉 Follow the Hireful Jobs channel on WhatsApp: https://lnkd.in/ghaHMBUB Telegram: https://t.me/hireful #javascript #webdevelopment #performance #frontend #nodejs #interviewprep #coding