Understanding JavaScript Prototype in a Simple Way

🚀 JavaScript Hoisting: A Small Interview Question That Confuses Many ✅ Today I came across an interesting JavaScript interview question : Why does console.log(bar) print the function instead of undefined? I was asked an interesting JavaScript question in an interview today, and it was a great reminder of how differently JavaScript handles hoisting for function expressions vs. function declarations. Here’s the concept behind the output: 1. **boo** is created using a function expression with **var**. Variables declared with var are hoisted, but only the variable name is initialized. The actual function value is not assigned until later. So when boo is logged before assignment, it returns undefined. 2. **bar** is created using a function declaration. Function declarations are fully hoisted. This means the entire function is placed into memory before any execution happens. So when **bar** is logged, JavaScript prints the complete function definition. 3. After execution reaches their definitions: Both **boo()** and **bar()** run normally because they now hold their respective function values. Key takeaway: **var** hoists only the variable, not the function value. Function declarations hoist both the name and the entire function body. A simple interview question, but a powerful reminder of how JavaScript behaves behind the scenes. #JavaScript #WebDevelopment #FrontendDeveloper #CodingInterview #TechInterview #JavaScriptTips #Hoisting #LearnToCode #Developers #Programming #MERNStack #ReactJS #NodeJS #100DaysOfCode

If you are preparing for Javascript Interview this quick revision topics might help you. Sharing this to stay accountable—and maybe help someone else preparing. Here’s what I’m actively revising 👇 ⚙️ Core JavaScript Internals • Type coercion and implicit conversions • var, let, const (hoisting, TDZ, reference errors) • Function hoisting vs variable hoisting • Primitive vs non-primitive data types • null vs undefined • Strict mode and why it exists ⏳ Async JavaScript & Execution Model • Event Loop (call stack, microtasks, macrotasks) • setTimeout / setInterval and how to stop them • Callbacks and callback hell • Promises (then, catch, finally, Promise APIs) • async/await vs promises • Writing async code in multiple patterns • Web Workers and off-main-thread execution 🧠 Functions, Scope & Objects • Closures (real use cases, not theory) • Currying (normal & infinite) • IIFE and use cases • Arrow functions vs normal functions • this keyword in different contexts • call, apply, bind • Shallow vs deep copy • Object.freeze() vs Object.seal() 🔗 Prototypes, OOP & FP • Prototypes & prototypal inheritance • Classes, constructors & super • Core OOP concepts in JavaScript • Functional programming vs OOP • Common design patterns • SOLID principles explained in JS terms 📦 Arrays, Objects & DOM • Array methods (map, filter, reduce, forEach) • for…of vs for…in • String, object & array utility methods • DOM vs BOM • Event bubbling, capturing & delegation 🚀 Performance & Practical Topics • Debouncing & throttling • Immutability • Memory leaks & garbage collection • Improving JavaScript performance • ES6+ features • Fetch vs Axios • REST APIs vs GraphQL • LocalStorage vs SessionStorage vs Cookies ✨ Extra practice alongside this list: – Writing polyfills (bind, map, reduce) – Solving real interview & machine-coding questions – Explaining answers out loud (this matters more than people think) If you’re revising JavaScript for interviews too 👇 What concepts would you add to this list? 👉 Follow Satyam Raj for more real interview insights, React fundamentals, and practical frontend engineering content. #JavaScript #FrontendDevelopment #InterviewPreparation #JSInterview #WebDevelopment #ReactJS #LearningInPublic #Developers #CodingLife #CareerGrowth

🔹 JavaScript Prototype & Prototypal Inheritance (Simple Explanation) This concept was asked in my recent interview, so sharing a clear and simple explanation. ✅ What is Prototype? In JavaScript, every object has a hidden link called [[Prototype]]. 👉 If a property or method is not found on the object, JavaScript looks for it in its prototype. This helps share methods without duplicating them. ✅ Prototype on Functions Every function has a .prototype property. We use it to add methods that all created objects can share. ✅ What is Prototypal Inheritance? When an object uses a method from its prototype, it is called prototypal inheritance. 🎯 Simple Summary Prototype → a hidden link that connects objects Prototypal inheritance → object accessing parent’s methods through prototype chain JavaScript searches: object → prototype → Object.prototype → null Understanding this makes JavaScript and React internals much clearer 🚀 #JavaScript #Frontend #Interviews #WebDevelopment #Learning

🧾 Day 27 | 90 Days of Full Stack Journey Today’s Topic: Top JavaScript Interview Questions I’ve Faced Interviews often test not just your coding skills, but also your understanding of JavaScript fundamentals. Here are some common JS questions I’ve personally come across 👇 🔑 Top JavaScript Interview Questions 1️⃣ What’s the difference between var, let, and const? 👉 Scope, hoisting behaviour, and reassignment rules. 2️⃣ Explain == vs ===. 👉 Loose vs. strict equality, and how type coercion works. 3️⃣ What are closures, and why are they useful? 👉 Functions that “remember” variables from their outer scope. 4️⃣ What is the event loop? 👉 How JavaScript handles asynchronous tasks using the call stack, task queue, and microtasks. 5️⃣ Difference between null and undefined? 👉 null = intentional empty value, 👉 undefined = value not assigned. 6️⃣ How does the this keyword work in JS? 👉 Depends on the execution context (regular functions vs. arrow functions). 7️⃣ Explain async/await vs Promises. 👉 async/await = cleaner, more readable syntax for handling promises. ⚡ Bonus Practical Questions How do you handle API errors in JS? What are truthy and falsy values? Can you explain hoisting with an example? 💡 Preparing for these topics not only helps in interviews but also makes you a stronger JavaScript developer. #JavaScript #InterviewPreparation #WebDev #FullStackDevelopment #CodingJourney #90DaysOfCode

JavaScript concepts I’m revising before my Frontend interviews. Some of these are frequently asked, some help build strong fundamentals. What I’m focusing on: • Type coercion & how JavaScript behaves under the hood • let, var, const (TDZ, hoisting, reference errors) • Hoisting (functions vs variables) • Primitive vs non-primitive data types • Async JavaScript — Event Loop, microtask & macrotask queues • Closures (with practical examples) • Currying (normal & infinite) • IIFE • Arrow functions vs normal functions • this keyword in different contexts • Prototypes & prototypal inheritance • Array methods (map, filter, reduce, forEach) • for...of vs for...in • Callbacks, callback hell & higher-order functions • Promises, .then, .catch & Promise methods • Event bubbling, capturing & delegation • LocalStorage vs SessionStorage vs Cookies • Strict mode • Web Workers • call, apply, bind • Shallow vs deep copy • Object.freeze() vs Object.seal() • Debouncing & throttling • SOLID principles (in simple JS terms) • Common design patterns • Array, string & object methods • null vs undefined • Nullish coalescing operator (??) • Writing async code in different ways • Promises vs async/await • DOM vs BOM • setTimeout & setInterval (and how to stop them) • Generators & iterators • Improving JavaScript performance • ES6+ features • Classes, constructors & super • Fetch vs Axios • REST APIs vs GraphQL • Functional programming vs OOP • Core OOP concepts in JavaScript ✨ A few extra things I’m practicing alongside this: – Polyfills (bind, map, reduce) – Memory leaks & garbage collection – Immutability – Real interview & machine-coding questions Sharing this to stay accountable and maybe help someone else who’s also preparing. If you’re revising JS for interviews too — 👉 what concepts would you add to this list? #JavaScript #FrontendDevelopment #InterviewPrep #LearningInPublic #WebDevelopment #JSInterview #ReactJS #Developers #CodingLife

🔥 Different Ways to Write Functions in JavaScript In JavaScript, functions are first-class citizens — and there’s more than one way to write them. Here are the most commonly used function types every JS developer should know 👇 ✅ Function Declaration ✅ Function Expression ✅ Arrow Function ✅ Anonymous Function ✅ IIFE (Immediately Invoked Function Expression) ✅ Object Method 💡 Why this matters? Understanding how and when to use each type helps in: Writing clean & readable code Handling callbacks and async logic Cracking JavaScript interviews Understanding frameworks like React internally 📌 Tip: Interviews don’t just check if you know functions — they check why you chose that syntax. If you’re learning JavaScript or preparing for interviews, save this post 🔖 More JS concepts coming soon 🚀 #JavaScript #FrontendDevelopment #WebDevelopment #JSFunctions #LearnJavaScript #CodingInterviews #ReactJS #Developers

🔥 Different Ways to Write Functions in JavaScript In JavaScript, functions are first-class citizens — and there’s more than one way to write them. Here are the most commonly used function types every JS developer should know 👇 ✅ Function Declaration ✅ Function Expression ✅ Arrow Function ✅ Anonymous Function ✅ IIFE (Immediately Invoked Function Expression) ✅ Object Method 💡 Why this matters? Understanding how and when to use each type helps in: Writing clean & readable code Handling callbacks and async logic Cracking JavaScript interviews Understanding frameworks like React internally 📌 Tip: Interviews don’t just check if you know functions — they check why you chose that syntax. If you’re learning JavaScript or preparing for interviews, save this post 🔖 More JS concepts coming soon 🚀 #JavaScript #FrontendDevelopment #WebDevelopment #JSFunctions #LearnJavaScript #CodingInterviews #ReactJS #Developers

🚀 JavaScript Interview Question That Many Developers Get Wrong! I recently came across an interesting JavaScript interview question: 💡 What will be the output? ➡️ 10 🔍 Why? Because JavaScript has: Function scope Local variable shadowing Closures Even though x = 15 creates a global variable, the inner() function has its own: let x = 10; This local variable shadows the global one. So the global x never affects the value returned by inner(). Understanding these small details is what separates a good JS developer from a great one! 💪 🧠 Key Takeaways ✔ JavaScript is single-threaded but supports async behavior ✔ Local variables always override global variables ✔ Closures retain access to their lexical scope ✔ Missing let/const creates global variables (bad practice!) #javascript #webdevelopment #interview #coding #frontend #reactjs #mern #nextjs #learnjavascript #softwareengineering

🔥 Different Ways to Write Functions in #JavaScript In JavaScript, functions are first-class citizens — and there’s more than one way to write them. Here are the most commonly used function types every JS developer should know 👇 ✅ Function Declaration ✅ Function Expression ✅ Arrow Function ✅ Anonymous Function ✅ IIFE (Immediately Invoked Function Expression) ✅ Object Method 💡 Why this matters? Understanding how and when to use each type helps in: Writing clean & readable code Handling callbacks and async logic Cracking JavaScript interviews Understanding frameworks like React internally 📌 Tip: Interviews don’t just check if you know functions — they check why you chose that syntax. If you’re learning JavaScript or preparing for interviews, save this post 🔖 More JS concepts coming soon 🚀 Follow Rahul Choudhary for more. JavaScript Mastery w3schools.com #JavaScript #FrontendDevelopment #WebDevelopment #JSFunctions #LearnJavaScript #CodingInterviews #ReactJS #Developers

🔥 Most Repeated JavaScript Interview Questions 1. What is Hoisting in JavaScript? 2. Difference between var, let, and const. 3. What is the Event Loop? 4. What is the difference between synchronous and asynchronous code? 5. What are Promises and how do they work? 6. Difference between Promise.all, Promise.race, Promise.allSettled, and Promise.any. 7. What is async/await and how does it improve async code? 8. What are Closures? Explain with an example. 9. What is the Temporal Dead Zone (TDZ)? 10. How does the this keyword work in different contexts? 11. Difference between call, bind, and apply. 12. What is Event Bubbling and Capturing? 13. What is Event Delegation? 14. How does prototypal inheritance work? 15. How does the new keyword work internally? 16. What is the difference between == and === ? 17. What are Higher-Order Functions? 18. What is Debouncing? 19. What is Throttling? 20. What is the difference between map, filter, and reduce? 21. What is a shallow copy vs deep copy? 22. What is the spread operator and rest operator? 23. What is destructuring in JavaScript? 24. What are arrow functions and how do they differ from normal functions? 25. What is a callback function? 26. What is an IIFE (Immediately Invoked Function Expression)? 27. What is a module in JavaScript (ES modules vs CommonJS)? 28. What are microtasks vs macrotasks? 29. What is Optional Chaining (?.)? 30. What is Nullish Coalescing (??)? #JavaScript #JavaScriptInterview #FrontendDeveloper #WebDevelopment #ReactJS #CodingInterview #InterviewPreparation #FrontendInterview