JavaScript Debouncing Technique Explained

Day 2/50 – JavaScript Interview Question? Question: What's the difference between call(), apply(), and bind()? Simple Answer: All three methods allow you to set the this context explicitly. call() invokes the function immediately with arguments passed individually, apply() invokes it with arguments as an array, and bind() returns a new function with this bound permanently. 🧠 Why it matters in real projects: These methods are crucial when working with object methods, event handlers, and callbacks where you need precise control over the this context. They're especially important in React class components and when borrowing methods between objects. 💡 One common mistake: Using bind() and expecting the function to execute immediately. Remember, bind() returns a new function—it doesn't invoke it! 📌 Bonus: const person = { name: 'Alice' }; function greet(greeting) { console.log(`${greeting}, ${this.name}`); } greet.call(person, 'Hello'); // "Hello, Alice" greet.apply(person, ['Hi']); // "Hi, Alice" const boundGreet = greet.bind(person); boundGreet('Hey'); // "Hey, Alice" #JavaScript #WebDevelopment #Frontend #LearnInPublic #InterviewQuestions #Programming #TechInterviews

Day 17/50 – JavaScript Interview Question? Question: What is debouncing and how do you implement it? Simple Answer: Debouncing is a technique that delays function execution until a certain amount of time has passed since the last invocation. It's perfect for limiting how often a function runs in response to rapid events. 🧠 Why it matters in real projects: Debouncing is essential for optimizing search autocomplete, form validation, window resize handlers, and scroll events. Without it, you'd make hundreds of unnecessary API calls or trigger expensive calculations on every keystroke. 💡 One common mistake: Confusing debouncing with throttling. Debouncing waits for a pause in events, while throttling executes at regular intervals regardless of event frequency. 📌 Bonus: // Debounce implementation function debounce(func, delay) { let timeoutId; return function(...args) { clearTimeout(timeoutId); timeoutId = setTimeout(() => { func.apply(this, args); }, delay); }; } // Usage: Search autocomplete const searchAPI = (query) => { console.log('Searching for:', query); // Actual API call here }; const debouncedSearch = debounce(searchAPI, 500); // User types "javascript" // Only makes 1 API call after user stops typing for 500ms searchInput.addEventListener('input', (e) => { debouncedSearch(e.target.value); }); #JavaScript #WebDevelopment #Frontend #LearnInPublic #InterviewQuestions #Programming #TechInterviews

Day 13/50 – JavaScript Interview Question? Question: What is hoisting in JavaScript? Simple Answer: Hoisting is JavaScript's behavior of moving declarations to the top of their scope during the compilation phase. Function declarations are fully hoisted, var declarations are hoisted but initialized as undefined, and let/const are hoisted but remain in the Temporal Dead Zone. 🧠 Why it matters in real projects: Understanding hoisting helps you avoid confusing bugs and write more predictable code. It explains why you can call functions before they're declared and why accessing var variables before declaration returns undefined instead of an error. 💡 One common mistake: Thinking hoisting physically moves code. It doesn't—it's about when variables and functions are registered in memory during the creation phase. 📌 Bonus: // Function hoisting - works! greet(); // "Hello" function greet() { console.log("Hello"); } // var hoisting - returns undefined console.log(name); // undefined (not ReferenceError) var name = "Alice"; // let/const - Temporal Dead Zone console.log(age); // ReferenceError let age = 25; // Function expressions are NOT fully hoisted sayHi(); // TypeError: sayHi is not a function var sayHi = function() { console.log("Hi"); }; #JavaScript #WebDevelopment #Frontend #LearnInPublic #InterviewQuestions #Programming #TechInterviews

Recent javascript interview questions I was interviewed. Though i wasn't selected but it gave me clear picture of the missing gaps. When i retrospect : Idea here is not just understanding the concepts is enough, you need to practice them with examples to stay with them to demonstrate when asked. Most intervewiers start with asking its definition and then a followup to demonstrate with an example problem to be given to you. Also very importantly simulate to build logic under pressurized circumstances (This can be done by keeping consistency in writing atleast 1 or 2 programs everyday to solve from simple to medium complexity problems). You may start with already seeing the solution to program them to 'wet' yourself but over the time start thinking first to build a pseudocode and then gradually uplift to solve problems atleast partially before looking for answers. Key here is : Patience and the practice and I truly mean here after experiencing the rejection under the hot seat. 1.) Event loop test by predicting output below : console.log('1'); console.log('2'); setTimeout(() => { console.log("This message appears after 2 seconds."); }, 0) Promise.resolve(console.log('4')); console.log('5'); 2.) Implement to sort by ID and then by score : const users = [{ id: '3', name: 'Alex', score: '45'}, { id: '4', name: 'Steve', score: '10'}, { id: '1', name: 'John', score: '24'}, { id: '2', name: 'James', score: '45'}]; 3.) write a closure to increment/decrement count in javascript 4.) What is event propagation and delegation, stateless vs stateful Vs Pure components 5.) What are synthetic events , throttling and debouncing 6.) React lifecycle and what is producer and consumer in Context in react 7.) what is CORS 8.) CSS rendering and styling 9.) Different types of Promise with specifically allSettled.

Day 20/50 – JavaScript Interview Question? Question: What is prototypal inheritance in JavaScript? Simple Answer: Prototypal inheritance is JavaScript's mechanism for objects to inherit properties and methods from other objects through the prototype chain. When you access a property, JavaScript first checks the object itself, then walks up the prototype chain until it finds the property or reaches null. 🧠 Why it matters in real projects: Understanding prototypes is fundamental to JavaScript's object model. It's how classes work under the hood, how built-in methods like Array.prototype.map() are available, and how you can extend native objects or create efficient object hierarchies. 💡 One common mistake: Confusing __proto__ (the actual link) with prototype (the property on constructor functions). Also, modifying built-in prototypes like Array.prototype in production code is considered a bad practice. 📌 Bonus: // Constructor function function Person(name) { this.name = name; } // Add method to prototype (shared by all instances) Person.prototype.greet = function() { return `Hello, I'm ${this.name}`; }; const alice = new Person('Alice'); alice.greet(); // "Hello, I'm Alice" // Prototype chain alice.hasOwnProperty('name'); // true (own property) alice.hasOwnProperty('greet'); // false (inherited) alice.__proto__ === Person.prototype; // true // Modern ES6 class syntax (same prototype underneath) class Employee extends Person { constructor(name, title) { super(name); this.title = title; } } const bob = new Employee('Bob', 'Developer'); console.log(bob.greet()); // Inherits from Person #JavaScript #WebDevelopment #Frontend #LearnInPublic #InterviewQuestions #Programming #TechInterviews #Prototypes #OOP

Stop guessing your way through JavaScript interviews. Frameworks like React and Next.js are powerful, but without mastering the JavaScript engine behind them, you’ll eventually hit a ceiling. I’ve compiled 50 essential JavaScript interview questions that every developer—from Junior to Senior—should be able to answer. Save this for interview prep or use it to assess your team’s fundamentals. JavaScript Fundamentals What is the difference between == and ===? What is the Temporal Dead Zone (TDZ)? How does hoisting work with var compared to let and const? What is type coercion in JavaScript? What is the difference between null and undefined? Functions & Scope What is a closure, and why are closures useful? What is the difference between arrow functions and regular functions, especially regarding this? What is an IIFE (Immediately Invoked Function Expression)? What is function currying? What is the difference between call, apply, and bind? Advanced JavaScript Concepts How does the Event Loop work with the Call Stack? What is the difference between microtasks and macrotasks, and which executes first? How does prototypal inheritance differ from classical inheritance? What is a pure function? How does JavaScript’s garbage collection work? Modern JavaScript (ES6+) What problem does Promise.allSettled() solve? How do destructuring and the spread/rest operators work? What is the difference between Map and Set, and when should you use WeakMap? What are generator functions, and when would you use them? What is the recommended error-handling pattern when using async/await? (Check the comments for the complete list of 50 questions.) The hard truth: You can build an entire application without understanding closures, but you cannot build a long-term career without mastering JavaScript fundamentals. When you master the basics, frameworks become tools—not crutches. Which of these concepts did you find the hardest to learn? Let’s discuss in the comments. #JavaScript #WebDevelopment #SoftwareEngineering #InterviewPreparation #Programming #DeveloperCareers

Day 11/50 – JavaScript Interview Question? Question: What is the difference between Promise.all() and Promise.race()? Simple Answer: Promise.all() waits for all promises to resolve (or one to reject) and returns an array of results. Promise.race() returns as soon as the first promise settles (resolves or rejects), ignoring the others. 🧠 Why it matters in real projects: Use Promise.all() when you need multiple API calls to complete before proceeding (like fetching user data and their posts). Use Promise.race() for implementing timeouts or choosing the fastest response from multiple sources. 💡 One common mistake: Not realizing that Promise.all() fails fast—if any promise rejects, the entire operation fails immediately, even if other promises are still pending. 📌 Bonus: // Promise.all - all must succeed const results = await Promise.all([ fetch('/api/user'), fetch('/api/posts'), fetch('/api/comments') ]); // If any fails, all fail // Promise.race - first one wins const result = await Promise.race([ fetch('/api/data'), new Promise((_, reject) => setTimeout(() => reject('Timeout'), 5000) ) ]); // Implements a 5-second timeout // Use Promise.allSettled() to get all results regardless of failures #JavaScript #WebDevelopment #Frontend #LearnInPublic #InterviewQuestions #Programming #TechInterviews

JavaScript Interview Question: Que: What is Throttling? Ans: Throttling in JavaScript is a technique used to limit how often a function can be executed within a specific period of time, regardless of how many times the triggering event occurs. This improves performance and responsiveness by preventing excessive function calls, especially for high-frequency events like scroll, resize, or mousemove. How Throttling Works?     - Throttling can be thought of as a valve or a security guard at a concert entrance. The first call to the throttled function executes immediately (or after the first interval, depending on implementation). Subsequent calls during a predefined "cooldown" period are ignored. Once the period has passed, the function can run again.     - This ensures that the function runs at a regular, controlled interval, rather than in a continuous burst that could overload the browser or server. Common Use Cases:     * Handling Scroll Events: Loading more content (infinite scrolling) or tracking scroll position without overwhelming the browser.     * Window Resize Events: Recalculating layout or redrawing elements at a controlled rate.     * API Rate Limiting: Ensuring that a button click or other interaction does not make hundreds of API requests in a short time.     * Animations and Drag-and-Drop: Improving the smoothness of resource-intensive animations and interactions by limiting updates. #javascript #throttling #conceptsOfJavaScript #freeLancer #reactJs #frontend #softwareDeveloper #nodeJs #backend #fullStack #interviewQuestion

Knowing JavaScript is no longer the differentiator. Most frontend candidates today know JavaScript. They know: - closures - async / await - debounce - React hooks - common patterns That’s no longer rare. What differentiates candidates now is how their understanding behaves under pressure. Modern interviews don’t stop at: “Can you explain this?” They move quickly to: “What happens if I change this?” “Why does this break here?” “What assumption is your code making?” “How would this behave in a real app?” Two people can give the same correct answer and get very different outcomes. Because one answer is stable. The other is fragile. Interviewers are no longer evaluating knowledge of concepts. They are evaluating depth of mental models. That’s why people blank out even when they “know the answer”, follow-ups feel disproportionately hard, preparation with isolated examples stops working. The real differentiator today is the ability to: - reason through changes - explain why something works - connect multiple concepts together - stay calm when the problem moves That’s not something you get from memorizing answers. It comes from intentional, depth-first preparation. This is also why my preparation material is structured the way it is. 👉 https://lnkd.in/g9hdUJkf What looks like Frontend Interview Blueprint on the surface is: 📘 300+ JavaScript & React interview questions. What people discover after downloading is: a second book with 📘 180+ JavaScript concepts explained in depth. ✅️ detailed breakdowns of why things behave the way they do. ✅️ questions designed to trigger follow-ups, not just first answers. That structure exists because interviews today don’t reward recall. They reward understanding that survives change.

#Interview Prep JavaScript array.sort() array.sort() is a JavaScript method used to arrange array elements in a specific order. By providing a compare function, we can control whether the sorting is ascending or descending. Example array Explanation ✅ arr = [6, 2, 4] arr.sort((a, b) => { return a - b; }) How TWO elements are chosen (visual angle) [ 6 , 2 , 4 ] ↑ ↑ a b JS picks neighbor elements a = 6 b = 2 Compare: 6 - 2 = 4 → swap After swap: [ 2 , 6 , 4 ] ▶️ Second pick [ 2 , 6 , 4 ] ↑ ↑ a b Now picks: a = 6 b = 4 Compare: 6 - 4 = 2 → swap After swap: [ 2 , 4 , 6 ] ▶️ Third (check) [ 2 , 4 , 6 ] ↑ ↑ a b Compare: 2 - 4 = -2 → no swap Array stays same ✅ JS always picks TWO values Assigns: first value → a second value → b It compares adjacent elements Moves forward like a sliding window [ a , b ] → compare → swap / no swap → move right 🔄 Same idea for descending arr.sort((a,b) => { return b - a }) [ 6 , 2 , 4 ] ↑ ↑ a b 2 - 6 = -4 → no swap → bigger stays first Result: [ 6 , 4 , 2 ] #JavaScript #Frontend #WebDevelopment #CodingTips #LinkedInLearning #ArrayMethods #Interview