JavaScript Interview Prep: Microtasks vs Macrotasks

🚀 TIL in JavaScript typeof null returns "object" 🤯 Yes, this is real — and it’s one of the oldest JavaScript quirks. 🧠 null means no value, but JavaScript still treats it as an "object" due to a historical bug. Example: ✔ typeof 10 → "number" ✔ typeof "JS" → "string" ✔ typeof null → "object" ❌ 📌 Always check null explicitly in real-world code and interviews. #JavaScript #WebDevelopment #FrontendDeveloper #CodingTips #TodayILearned

The most frequently asked question in the JavaScript interview is: "How prototypal inheritance works in JavaScript"? This is the question that most developers struggle to explain. So I have written an article explaining it in detail and in easy-to-understand language. 𝗖𝗵𝗲𝗰𝗸 𝗼𝘂𝘁 𝘁𝗵𝗲 𝗮𝗿𝘁𝗶𝗰𝗹𝗲 𝗹𝗶𝗻𝗸 𝗶𝗻 𝘁𝗵𝗲 𝗰𝗼𝗺𝗺𝗲𝗻𝘁 𝘁𝗼 𝗯𝗲𝘁𝘁𝗲𝗿 𝘂𝗻𝗱𝗲𝗿𝘀𝘁𝗮𝗻𝗱 𝗽𝗿𝗼𝘁𝗼𝘁𝘆𝗽𝗲 𝗮𝗻𝗱 𝗽𝗿𝗼𝘁𝗼𝘁𝘆𝗽𝗮𝗹 𝗶𝗻𝗵𝗲𝗿𝗶𝘁𝗮𝗻𝗰𝗲. 𝘍𝘰𝘳 𝘮𝘰𝘳𝘦 𝘴𝘶𝘤𝘩 𝘶𝘴𝘦𝘧𝘶𝘭 𝘤𝘰𝘯𝘵𝘦𝘯𝘵, 𝘥𝘰𝘯'𝘵 𝘧𝘰𝘳𝘨𝘦𝘵 𝘵𝘰 𝘧𝘰𝘭𝘭𝘰𝘸 𝘮𝘦. #javascript #reactjs #nextjs #webdevelopment

📘 JavaScript Handwritten Notes – Toppers World ✍️ Sharing my JavaScript handwritten notes from Toppers World, which helped me strengthen my core fundamentals and understanding of key concepts. These notes are great for: ✅ Quick revision ✅ Interview preparation ✅ Understanding JavaScript basics clearly Topics include variables, functions, closures, promises, async/await, DOM concepts, and more – explained in a simple and easy-to-understand way. Hope this helps fellow learners and developers 🚀 Feel free to check it out and share your feedback! #JavaScript #HandwrittenNotes #WebDevelopment #FrontendDeveloper #LearningJourney #InterviewPreparation #ToppersWorld #Sidtech

One of the most important interview questions is: 👉 “Explain the JavaScript Prototype Object.” To simplify this concept, I’ve written a detailed article that breaks it down with diagrams and easy explanations. 📖 Read here: https://lnkd.in/dQEpGNfa #JavaScript #nomadcoder

🤔JavaScript behaves differently with values depending on what you’re working with and this trips up a lot of interview answers. 🧠 JavaScript interview question What is the difference between primitive and reference types? ✅ Short answer • Primitives are copied by value • Objects are copied by reference • Equality checks references, not structure 🔍 A bit more detail • Primitive types number, string, boolean, null, undefined, symbol, bigint Stored as values Assigning or passing them creates a copy • Reference types objects, arrays, functions Variables store a reference to the same object Mutating through one reference affects all others • Equality {} === {} is false Same shape does not mean same reference 💻 Example // primitive copy let a = 5 let b = a b = 7 console.log(a) // 5 // reference copy const p = { n: 1 } const q = p q.n = 2 console.log(p.n) // 2 ⚠️ Small but important detail JavaScript always passes arguments by value. For objects, that value is the reference. Reassigning a parameter does nothing. Mutating the object does. I’m sharing one JavaScript interview-style question per day to build calm, solid fundamentals step by step. #javascript #frontend #interviewprep #webdevelopment

🚨 One of the most commonly asked JavaScript interview questions — Hoisting Before the code runs, JavaScript sets up memory for variables and functions. • Function declarations are fully hoisted and can be called before they are written • var is hoisted but initialized as undefined • let and const are hoisted but remain inaccessible until declared (TDZ) Understanding hoisting helped me write cleaner and more predictable JavaScript ⚡ #JavaScript #Hoisting #JSInterview #FrontendDevelopment

Day 8/50 – JavaScript Interview Question? Question: What's the difference between == and === in JavaScript? Simple Answer: == (loose equality) performs type coercion before comparison, while === (strict equality) checks both value and type without any conversion. 🧠 Why it matters in real projects: Using === prevents subtle bugs caused by unexpected type coercion. It makes your code more predictable and is considered a best practice in modern JavaScript development. Most linters enforce strict equality by default. 💡 One common mistake: Thinking that == is just "more forgiving" without understanding the complex coercion rules that can lead to confusing results like [] == ![] being true. 📌 Bonus: // Confusing results with == 0 == false // true '' == false // true null == undefined // true '0' == 0 // true // Clear and predictable with === 0 === false // false '' === false // false null === undefined // false '0' === 0 // false // Exception: checking for null/undefined if (value == null) // checks both null AND undefined #JavaScript #WebDevelopment #Frontend #LearnInPublic #InterviewQuestions #Programming #TechInterviews

Day 1/50 – JavaScript Interview Question? Question: What is the Temporal Dead Zone (TDZ) in JavaScript? Simple Answer: The Temporal Dead Zone is the period between entering a scope and the actual declaration of a let or const variable, during which the variable cannot be accessed. 🧠 Why it matters in real projects: Understanding TDZ helps you avoid ReferenceError bugs in your applications. Unlike var which returns undefined when accessed before declaration, let and const throw errors, making your code more predictable and easier to debug. 💡 One common mistake: Assuming that because let and const are "hoisted" like var, they can be accessed before their declaration. They are hoisted, but remain uninitialized in the TDZ. 📌 Bonus: console.log(myVar); // undefined console.log(myLet); // ReferenceError: Cannot access before initialization var myVar = 1; let myLet = 2; #JavaScript #WebDevelopment #Frontend #LearnInPublic

🧠 What happens before JavaScript executes? Before your JavaScript code runs, the engine parses it, creates the execution context, allocates memory, hoists variables/functions, and prepares optimized code using JIT compilation. This explains hoisting, the temporal dead zone, and many tricky JS behaviors — and it’s a must-know concept for JavaScript interviews, especially for frontend and full-stack roles. 📘 I’ve written a detailed article on this topic on Medium — link shared in the comments. #JavaScript #Interviews #WebDevelopment #Frontend #Engineering

🧠 JavaScript Skills Every Frontend Developer Should Know I regularly revise these JavaScript concepts because they show up in real projects and interviews: • Closures • Promises & async/await • map, filter, reduce • Scope & hoisting • Event handling Strong fundamentals make React easier and cleaner to write. #JavaScript #FrontendDeveloper #ReactJS #InterviewPrep #LearningInPublic