Event Loop in JavaScript Explained

🚀 Day 3 – Crack Interviews Series 🔹 Topic: What is Async/Await in JavaScript? Async/Await is a cleaner way to handle asynchronous code built on top of Promises. 👉 It makes async code look like synchronous code. 💡 Real Example: function fetchData() { return new Promise((resolve) => { setTimeout(() => resolve("Data received"), 1000); }); } async function getData() { const result = await fetchData(); console.log(result); } getData(); 🎯 Interview Question: What happens if we don’t use "await" inside an async function? 👉 Answer: The function will return a Promise immediately without waiting for the result. 💼 Pro Tip: Always use "try...catch" with async/await for proper error handling. 👇 Do you use async/await in all your projects? #javascript #webdevelopment #nodejs #frontend #interviewprep #coding #developers

🚀 Day 4 – Crack Interviews Series 🔹 Topic: What is Hoisting in JavaScript? Hoisting is JavaScript’s behavior of moving declarations to the top of their scope before execution. 👉 Important: - "var" is hoisted and initialized with "undefined" - "let" & "const" are hoisted but stay in Temporal Dead Zone (TDZ) 💡 Real Example: console.log(a); // undefined var a = 10; console.log(b); // ReferenceError let b = 20; 🎯 Interview Question: Why does "let" throw error but "var" does not? 👉 Answer: Because "let" is in Temporal Dead Zone until initialized, while "var" is initialized with "undefined". 💼 Pro Tip: Avoid "var" in modern JavaScript — prefer "let" and "const" for safer scope handling. 👇 Have you ever faced a bug because of hoisting? #javascript #webdevelopment #frontend #nodejs #interviewprep #coding #developers

🚀 JavaScript Interview Question: Functions Today in my mock interview, I was asked: 👉 What is a function in JavaScript? 👉 How many types of functions are there? 👉 What is the syntax? ✅ What is a Function? A function in JavaScript is a reusable block of code designed to perform a specific task. It helps avoid repetition and makes code modular and organized. 📌 Types of Functions in JavaScript Function Declaration function greet() { console.log("Hello World"); } Function Expression const greet = function() { console.log("Hello World"); }; Arrow Function (ES6) const greet = () => { console.log("Hello World"); }; IIFE (Immediately Invoked Function Expression) (function() { console.log("Hello World"); })(); 💡 Why functions are important? ✔ Code reusability ✔ Better organization ✔ Easy debugging ✔ Cleaner and scalable code 📚 I’m currently learning JavaScript and improving my frontend development skills step by step. #JavaScript #FrontendDevelopment #ReactJS #WebDevelopment #MERNStack #LearningInPublic

Interviews are changing. It’s no longer about just using JavaScript features. It’s about understanding how they actually work. That’s where polyfills come in. Most developers can use: map(), filter(), bind(), promises… But very few can implement them from scratch. And that’s exactly what companies are testing now. Because polyfills reveal: Your core JavaScript knowledge How you handle edge cases Your problem-solving approach Also in real-world development: Not every browser supports modern features. Polyfills help you bridge that gap. So instead of just “using” JavaScript… 👉 Start rebuilding it. That’s what separates beginners from real engineers. #JavaScript #WebDevelopment #Frontend #CodingInterview #Developers #Programming #SoftwareEngineering #Tech #LearnToCode #JS #CareerGrowth

🚀 Day 8 – Crack Interviews Series 🔹 Topic: What is Prototype in JavaScript? Every JavaScript object has a hidden property called prototype that allows it to inherit properties and methods from other objects. 👉 This is how inheritance works in JavaScript. 💡 Real Example: function Person(name) { this.name = name; } Person.prototype.greet = function () { console.log("Hello " + this.name); }; const user = new Person("Priyanshu"); user.greet(); // Hello Priyanshu 👉 "greet()" is not inside the object, but still accessible via prototype. 🎯 Interview Question: What is the prototype chain? 👉 Answer: It’s a chain of objects where JavaScript looks for properties if not found in the current object. 💼 Pro Tip: Modern JavaScript uses "class", but under the hood it still works with prototypes. 👇 Have you explored prototype vs class deeply? 👉 Follow the Hireful Jobs channel on WhatsApp: https://lnkd.in/ghaHMBUB Telegram: https://t.me/hireful #javascript #webdevelopment #frontend #nodejs #interviewprep #coding #developers

Most developers don’t fail JavaScript interviews because they lack knowledge. They fail because they don’t understand the basics deeply enough. These simple DOM methods are used in almost every real project: • querySelector() → select elements • innerText → update text content • innerHTML → modify structure • addEventListener() → handle user actions • classList → manage styles dynamically Sounds basic? Yes. But this is exactly where most mistakes happen. 👉 Clean DOM manipulation = better UI + better performance + fewer bugs If you truly understand these, you’re already ahead of 70% of developers. 💡 Don’t just memorize build small projects using them. Save this for later 📌 And follow for more real-world JavaScript concepts. #javascript #webdevelopment #frontend #coding #programming #developers #learncoding

JavaScript Interview Questions – Part 1 (Must Know for Developers!) I’ve compiled a powerful set of JavaScript concepts & interview questions that every developer should master 💡 From basics to advanced topics, this covers: -- Difference between undefined vs null -- Deep understanding of DOM & DOM Manipulation -- Event Propagation (Capturing, Target, Bubbling) -- == vs === (Most asked interview question!) -- Hoisting & Execution Context -- Closures (with real examples) -- this keyword behavior (Tricky but important!) -- Higher Order Functions & Callbacks -- Custom implementations of map, filter, reduce -- Async JavaScript (Callbacks, Promises, Async/Await) 📘 This is not just theory — it includes practical examples, edge cases, and interview-focused explanations. 💬 Whether you're preparing for interviews or strengthening your fundamentals, this will help you level up your JavaScript game. 🔥 I’ll be sharing more parts soon on WhatApp Group (https://lnkd.in/dFyqKJU3) — stay tuned! 👉 Let me know in the comments: Which JavaScript topic do you find the most confusing? #JavaScript #WebDevelopment #Frontend #Programming #Coding #InterviewPrep #Developers #LearnToCode #Tech #SoftwareEngineering #MohitDecodes

🚀 JavaScript Function Types Explained (Simple & Clear Guide) Functions are the backbone of JavaScript. Mastering them helps you write cleaner, more efficient, and scalable code. Here are the key function types every developer should know: 🔹 Function Declarations – The standard and most widely used 🔹 Function Expressions – Useful for more control and flexibility 🔹 Arrow Functions (=>) – Modern, concise, and popular in React 🔹 Callback Functions – Essential for handling asynchronous operations 🔹 IIFE (Immediately Invoked Function Expression) – Executes immediately after definition 🔹 Higher-Order Functions – Functions that take or return other functions 💡 Understanding these concepts will boost your coding skills and help you perform better in technical interviews. 👉 Which function type do you use the most in your projects? Let’s discuss in the comments 👇 #JavaScript #WebDevelopment #Frontend #Coding #ReactJS #NodeJS #Programming #Interviews #Tips #Tricks

Being strong in JavaScript and TypeScript is the gateway to crack interviews. Not just surface level. Get into depth. Look into how it actually works. Trust me, it gets interesting day by day. One such concept which I loved and still love to explain and solve: Event Loop Most developers know the definition. Few actually feel how it works. Let me break it down: JavaScript is single-threaded. One call stack. One thing at a time. So how does it handle setTimeout, API calls, and UI updates — all without freezing? That's where the Event Loop steps in. Here's what's actually happening under the hood: 🔹 Call Stack — Where your code executes. Functions get pushed in, popped out. 🔹 Web APIs — setTimeout, fetch, DOM events? These are handed off to the browser. JS doesn't wait. 🔹 Callback Queue (Macrotask Queue) — Once a Web API finishes, its callback waits here. 🔹 Microtask Queue — Promises land here. Higher priority than the callback queue. 🔹 Event Loop — Constantly watching. The moment the call stack is empty, it picks from the microtask queue first, then the callback queue. A classic interview question that trips people up: console.log("1"); setTimeout(() => console.log("2"), 0); Promise.resolve().then(() => console.log("3")); console.log("4"); The Output: 1 → 4 → 3 → 2 Why? Because setTimeout goes to the callback queue, but the Promise microtask jumps ahead in priority — even with a 0ms delay. This is the kind of depth that separates a developer who uses JavaScript from one who understands it. What's your favorite JS concept that changed how you think about code? Drop it in the comments! #JavaScript #TypeScript #EventLoop #WebDevelopment #InterviewPrep #FrontendDevelopment #JSDeepDive #LearningEveryDay