JavaScript Event Loop: Microtasks vs Macrotasks Explained

🚀 JavaScript Fundamentals Series — Part 1 Before learning frameworks, async code, or complex patterns… you need to understand the core building blocks of JavaScript. Everything in JavaScript starts with variables and data types. In this guide you'll learn: • var, let, and const differences • Primitive vs Reference types • How JavaScript stores data in memory • Why type coercion causes weird bugs • Common mistakes developers make If your foundation here is strong, the rest of JavaScript becomes MUCH easier. I wrote a full guide explaining it clearly with diagrams and examples. Read here 👇 https://lnkd.in/dz_TuuVT Hitesh Choudhary Chai Aur Code Piyush Garg Akash Kadlag #javascript #webdevelopment #coding #learnjavascript

Just published a new blog on JavaScript Execution Context, Hoisting, TDZ, and Call Stack. While learning these concepts, I realized how important it is to understand how JavaScript actually executes code behind the scenes. It helps explain a lot of behaviors that otherwise feel confusing. In this blog, I’ve tried to break down these concepts simply and clearly. If you’re learning JavaScript or revisiting the fundamentals, feel free to check it out: https://lnkd.in/d6S5HGPy Open to feedback and suggestions. #JavaScript #LearningInPublic #WebDevelopment #BuildInPublic #ChaiCode #Hoisting

Just wrapped up my 3rd JavaScript project - a Random Quote Generator! 🎲 This one was different. Not because it's complex (it's actually pretty simple), but because I finally *got* async/await. I've been reading about Promises and .then() chains for weeks. Understood them conceptually, but they always felt... messy? Like I was fighting with the syntax instead of just writing code. Then I rebuilt this project using async/await and something clicked. The code just reads like normal code. Top to bottom. No nesting. Clean error handling. It finally makes sense. Here's what changed for me: Before (with .then chains): fetch(url)  .then(response => response.json())  .then(data => displayQuote(data))  .catch(error => handleError(error)); After (with async/await): async function getQuote() {  try {   const response = await fetch(url);   const data = await response.json();   displayQuote(data);  } catch (error) {   handleError(error);  } } Same functionality. Way easier to read. The debugging moment that taught me the most: Spent 15 minutes wondering why my quote wasn't displaying. Kept getting "undefined." Turns out the API returns an array, not an object. So data.quote didn't work. But data[0].quote did. Simple fix. But it taught me to always console.log() API responses first before assuming their structure. Built in about an hour. Learned way more than an hour's worth. Small projects. Real learning. 🌐 Live: https://lnkd.in/gsf3dvfe 💻 Code: https://lnkd.in/gt2mwRFH #JavaScript #AsyncAwait #WebDevelopment #100DaysOfCode #LearningInPublic

I wrote a beginner-friendly post on JavaScript objects. It covers what objects are, why they’re useful, and how they help group related data together in a structured way, with simple examples. If you’re learning JavaScript basics, this might be helpful: https://lnkd.in/gVf6z8Yy Feedback is welcome. Hitesh Choudhary Piyush Garg

𝗧𝗵𝗲 𝗘𝘃𝗲𝗻𝘁 𝗟𝗼𝗼𝗽: 𝗦𝘆𝗻𝗰𝗵𝗿𝗼𝗻𝗼𝘂𝘀 𝗮𝗻𝗱 𝗔𝘀𝘆𝗻𝗰𝗵𝗿𝗼𝗻𝗼𝘂𝘀 𝗖𝗼𝗱𝗲 You want to understand how JavaScript works. Let's look at an example: console.log("Start"); setTimeout(() => { console.log("Timeout"); }, 0); Promise.resolve().then(() => { console.log("Promise"); }); console.log("End"); What do you think the output will be? - Start - End - Promise - Timeout This happens because JavaScript runs code in a specific order. - Synchronous code runs line by line. - Asynchronous code runs in the background. JavaScript uses something called the Event Loop to manage tasks. - The Event Loop checks for tasks to run. - It uses two queues: microtasks and macrotasks. - Microtasks are small, important tasks like Promises. - Macrotasks are normal asynchronous tasks like setTimeout. When you run the code, here's what happens: 1. JavaScript runs the synchronous code: Start 2. It schedules the setTimeout task. 3. It runs the final synchronous line: End 4. The Event Loop checks the microtask queue and runs the Promise callback: Promise 5. Finally, it checks the macrotask queue and runs the setTimeout callback: Timeout Understanding the Event Loop helps you work with: - API requests - Asynchronous tasks Try to predict the output of this code: console.log("A"); setTimeout(() => console.log("B"), 0); Promise.resolve().then(() => console.log("C")); console.log("D"); Use the rule we learned: - Synchronous code - Microtasks (Promises) - Macrotasks (Timers, setTimeout) Write your answer in the comments. Source: https://lnkd.in/gbAJefcw

🚀 JavaScript Fundamentals Series — Part 4 Functions are where JavaScript becomes powerful and reusable. Instead of repeating code, functions let you create reusable logic blocks. In this guide you'll learn: • What functions actually are • Parameters vs arguments • Return values • Function declarations vs expressions • How functions organize your code Functions are the foundation of almost everything in JavaScript. Full guide 👇 https://lnkd.in/dtgFaW2r #javascript #webdevelopment #coding

🚀 Just Published: Blog 4 of Javascript blog series JavaScript Array Methods Made Simple If you're learning JavaScript, mastering array methods is a must. In this blog, I’ve explained: ✔️ push() & pop() ✔️ shift() & unshift() ✔️ map() ✔️ filter() ✔️ reduce() (beginner-friendly) ✔️ forEach() If you’re still using long for-loops everywhere, this will change how you write JavaScript. 🔗 Read here: https://lnkd.in/gv5vsmu9 Would love your feedback! Hitesh Choudhary, Piyush Garg and Chai Aur Code team #JavaScript #WebDevelopment #Coding #Beginners #Frontend #LearnToCode

🚀 Just published a new blog on Understanding Objects in JavaScript. In this article, I explain what objects are, why they are important in JavaScript, and how they store data using key–value pairs. I also covered creating objects, accessing properties using dot and bracket notation, updating values, adding or deleting properties, and looping through object keys. 📖 Read the full article here: https://lnkd.in/gbxx6N2G Inspired by the amazing teaching of Hitesh Choudhary Sir and Piyush Garg Sir from Chai Aur Code. ☕💻 #javascript #webdevelopment #learninginpublic #chaiAurCode

Small JavaScript bugs keep escaping to production and breaking critical user flows. Debugging inconsistent runtime behavior steals time from feature delivery. ────────────────────────────── Unlocking JavaScript with Proxy and Reflect API Explore the powerful Proxy and Reflect APIs in JavaScript that can elevate your coding skills. #javascript #proxy #reflect #webdevelopment ────────────────────────────── Core Concept Have you ever wished you could intercept and customize operations on objects in JavaScript? The Proxy and Reflect APIs allow you to do just that, making your code more flexible and powerful. Key Rules • Use Proxy to define custom behavior for fundamental operations (e.g., property lookup, assignment). • Reflect provides methods for interceptable JavaScript operations, acting as a companion to Proxy. • Remember to keep your use cases clear; these tools can add complexity if not applied thoughtfully. 💡 Try This const target = {}; const handler = { get: (obj, prop) => prop in obj ? obj[prop] : 'Property not found!' }; const proxy = new Proxy(target, handler); console.log(proxy.someProperty); ❓ Quick Quiz Q: What does the Proxy API allow you to do? A: Intercept and customize operations on objects. 🔑 Key Takeaway Embrace Proxy and Reflect to enhance your JavaScript code's functionality and behavior!

Many developers and students often get confused between JavaScript code execution for synchronous and asynchronous code. I was revisiting these fundamentals today and thought of sharing a simple breakdown that helped me connect all the dots. Here’s the Actual Flow Behind Node.js Execution JavaScript is Single-Threaded JavaScript runs on a single thread, meaning it executes one task at a time. This keeps things simple and avoids complex concurrency issues. But then the question is — How does Node.js handle multiple requests efficiently? That’s where V8, Event Loop, and libuv come into play. V8 Engine — The JavaScript Executor V8 is the engine that executes JavaScript code. It converts JavaScript into machine code. Handles synchronous code execution, so whenever sync code appears, It goes directly to Call Stack, V8 executes it immediately What Happens When Async Code Appears? When Node.js encounters async code like: setTimeout, File read, Database calls, API requests Instead of blocking execution, It sends async tasks to libuv libuv (C-Libarary) — The Background Worker libuv handles: Async I/O operations Thread pool tasks Event loop management Once async task completes: Callback goes to Callback Queue Event Loop — The Traffic Manager Event Loop continuously checks: Is Call Stack empty? Is there anything in Callback Queue? If both conditions satisfy: Event Loop pushes callback to Call Stack and V8 executes callback Final Flow Summary Sync Code → Call Stack → V8 executes Async Code → libuv Task Completed → Callback Queue Event Loop checks → Call Stack empty Callback → Call Stack V8 executes callback Understanding this core flow clears most of the confusion around synchronous vs asynchronous JavaScript in Node.js. #NodeJS #JavaScript #BackendDevelopment #EventLoop #V8 #libuv #AsyncProgramming #WebDevelopment #Learning #SoftwareEngineering