🚀 FREE LIVE MERN Stack Course | Day 14 | Asynchronous JavaScript (Callbacks, Promises, Async/Await)

🎓 Join my FREE LIVE MERN Stack Course — started from 1st November, streaming every day on YouTube Live! Welcome to Day 13 of the MERN Stack Live Training Series! In this session, we dive deep into Asynchronous JavaScript, one of the most important concepts used in real-world web development — especially in React, Node.js, and API-driven applications. You’ll learn exactly how JavaScript handles async operations using callbacks, promises, and async/await, how the event loop works, and how to avoid callback hell. We also explore real-world scenarios like API calls, timeouts, and handling multiple promises together. 🔍 Topics Covered (Day 14 – Asynchronous JavaScript) 1️⃣ Callbacks – The Beginning of Async JS What are callbacks? setTimeout, setInterval examples Callback pitfalls What is callback hell? Why callback hell is bad (pyramid of doom) 2️⃣ Promises – Modern Way to Handle Async Code Understanding Promise states (pending, fulfilled, rejected) Creating a promise using new Promise() resolve and reject Consuming promises with .then(), .catch(), .finally() Chaining promises to avoid callback hell 3️⃣ Async / Await – Cleaner & Modern Approach Why async/await? Writing synchronous-looking async code Using await to pause promise execution Error handling using try...catch Real API examples (fetch) 4️⃣ Promise Utility Methods (Must Know for Interviews) Promise.all() → parallel execution Promise.allSettled() → results of all Promise.race() → first settled (resolve/reject) Promise.any() → first fulfilled Promise.resolve() Promise.reject() 5️⃣ Understanding the Event Loop Call stack, Web APIs, Callback queue How JavaScript executes async code internally Microtask queue vs macrotask queue Why promises run faster than setTimeout 6️⃣ Real-World Use Cases API calls Timeout + retry logic Parallel API requests Loading states in React Async Node.js operations (file reading, database queries) 💡 Learning Outcome By the end of this lesson, you’ll understand how JavaScript actually works behind the scenes when handling asynchronous code. You will learn how to: ✔ Write clean async code using async/await ✔ Avoid callback hell ✔ Manage multiple asynchronous operations ✔ Handle API responses properly ✔ Use Promise utilities to optimize performance ✔ Debug async issues easily These concepts are essential for React, Node.js, Express, MongoDB, and real-world project development. 💻 What You’ll Learn in the MERN Stack Course: ✅ HTML, CSS, JavaScript (Core + Advanced) ✅ React.js (Frontend) ✅ Node.js & Express.js (Backend) ✅ MongoDB (Database) ✅ API Development + Asynchronous JS ✅ Real Projects + Deployment ✅ Interview Preparation (Frontend + MERN) ✅ AI Tools for Developers 🕗 Time: 9:30 PM – 11 PM (Daily) 📍 Platform: YouTube Live 💬 Join Completely FREE ✨ Be part of this Full-Stack journey — Subscribe now and don’t miss any class! For People search : JavaScript Async Asynchronous JavaScript JavaScript Callbacks Callback Hell Explained Promises in JavaScript async await javascript JavaScript Promises Tutorial Promise all promise race Event Loop JavaScript JavaScript microtask queue javascript settimeout javascript setinterval js callback vs promise js async await vs promise javascript event loop explained mern stack course free mern stack course mern stack full course learn mern stack 2025 javascript full course javascript hindi tutorial mern live class codewithprashant react node express mongodb mern stack tutorial for beginners mern stack for beginners javascript interview preparation frontend developer course javascript course 2025 mern stack developer web development course hindi javascript complete course asynchronous programming javascript javascript fetch api javascript api call tutorial javascript promise vs callback javascript callback hell solution nodejs asynchronous programming react async await tutorial javascript beginner to advanced free coding course hindi learn to code 2025 js synchronous vs asynchronous javascript blocking nonblocking js promise chaining js async await try catch javascript concurrency javascript runtime explained youtube live coding hindi daily live mern training learn javascript step by step best javascript course 2025 free live coding class mern stack roadmap 🔖 Tags / Keywords #MERNStack #JavaScript #AsyncJavaScript #Callbacks #Promises #AsyncAwait #EventLoop #CodeWithPrashant #FullStackDeveloper #LearnCoding #JavaScriptTutorial #FrontendDevelopment #ReactJS #NodeJS #ExpressJS #MongoDB #WebDevelopment #JavaScriptCourse #CodingInHindi #MERNTraining #LiveCoding #ProgrammingInHindi #JavaScriptForBeginners #ES6 #PromiseAll #CallbackHell #FreeCodingClass #MERN2025 #ReactDeveloper #BackendDeveloper #APIs #LearnJavaScript