How to Use Async Iterators in JavaScript for Efficient Async Workflows

Understanding the Event Loop in JavaScript: JavaScript is a single-threaded language, meaning it can execute one command at a time. Yet, it handles multiple operations like API calls, timers, and user events without blocking the main thread. This is possible because of the event loop. What is the event loop? The event loop is a mechanism that enables JavaScript to perform non-blocking, asynchronous operations. It continuously monitors the call stack and callback queues, ensuring that tasks are executed in the correct order without freezing the application. How It Works: * Call Stack: The place where your main JavaScript code runs line by line. * Web APIs: Handle asynchronous tasks like setTimeout, fetch, or event listeners. * Callback Queue: Stores callback functions waiting to be executed after asynchronous operations finish. * Event Loop: Keeps checking if the Call Stack is empty. If it is, it takes the next task from the queue and pushes it to the call stack for execution. Example: console.log("Start"); setTimeout(() => { console.log("Timeout executed"); }, 0); console.log("End"); Output: Start End Timeout executed Even though the timeout delay is set to 0 milliseconds, the message “Timeout executed” appears last. This is because the event loop waits for the call stack to be cleared before executing queued callbacks. Why It Matters: * Helps JavaScript manage asynchronous operations effectively. * Prevents the browser from freezing during heavy tasks. * Ensures smooth execution of user interactions and background processes. * Essential for understanding asynchronous behavior and writing efficient JavaScript code. KGiSL MicroCollege #JavaScript #EventLoop #AsynchronousProgramming #WebDevelopment #FrontendDevelopment #Programming #JSConcepts #WebAppDevelopment #FullStackDeveloper #Coding #DeveloperCommunity #LearnToCode #SoftwareEngineering #CodeNewbie #TechEducation #SoftwareDeveloper #FrontendEngineer #CodeTips #ModernWeb #WebDevCommunity #ProgrammingConcepts #SoftwareDevelopment #CleanCode #CodeJourney #JSDeveloper #TechLearning #WebDesign #CodingDaily #DeveloperLife #ES6 #CodeLogic

I had an argument today on a topic which can be skipped very easily (You don't want to miss reading it) The issue was with understanding the following: ↳ setState() ↳ Mutable & Immutable ↳ Deep and Shallow Copy This looks like an easy concept, but if missed, you will keep scratching your head, or just do vibe coding (which is not recommended) const myInitialState = [ { name: 'name', age: 10 }, { name: 'name1', age: 20 }]; ❌ setState(prevState => prevState.sort((a, b) => a.age - b.age)); ✅ setStatet(prevState => { const sorted = [...prevState]; sorted.sort((a, b) => a.age - b.age)); return sorted; }); Q1. Why does updating the older value doesn't work, and the later works? Q2. Creating a copy via [...prevState] is still a shallow copy, then how does React knows something has changed? Answer 1. The reference matters here. When you change something to the older value, the reference doesn't change, and React thinks, it is still unchanged, hence, no re-render trigger, and no UI updates. Answer 2. Even when you create shallow copy, you are creating a new reference. Creating a new array via "[ ]" → Then shallow copy the items using Spread operator. So the reference of sorted and prevState changes. As soon as React sees that in the return, it triggers re-render, as per "Diffing Algorithm". If you have learnt something new, let your friend learn it too via Repost ♻️ P.S. I have bonus questions in the comment section. Let's check how good do you know React #reactjs #react #javascript #coding #programming #softwareengineering #frontend

𝟵𝟬% 𝗼𝗳 𝗗𝗲𝘃𝗲𝗹𝗼𝗽𝗲𝗿𝘀 𝗱𝗼𝗻’𝘁 𝗸𝗻𝗼𝘄 𝗵𝗼𝘄 𝗝𝗮𝘃𝗮𝗦𝗰𝗿𝗶𝗽𝘁 𝗿𝘂𝗻𝘀 𝘂𝗻𝗱𝗲𝗿 𝘁𝗵𝗲 𝗵𝗼𝗼𝗱. 𝗬𝗼𝘂𝗿 𝗯𝗿𝗼𝘄𝘀𝗲𝗿 𝗿𝗲𝗮𝗱𝘀, 𝗰𝗼𝗺𝗽𝗶𝗹𝗲𝘀, 𝗮𝗻𝗱 𝗰𝗹𝗲𝗮𝗻𝘀 𝗶𝘁 - 𝗶𝗻 𝗿𝗲𝗮𝗹 𝘁𝗶𝗺𝗲. 👇 🔹 𝗦𝘁𝗲𝗽 𝟭: 𝗣𝗮𝗿𝘀𝗶𝗻𝗴 (𝗨𝗻𝗱𝗲𝗿𝘀𝘁𝗮𝗻𝗱𝗶𝗻𝗴 𝘁𝗵𝗲 𝗖𝗼𝗱𝗲) • You write JavaScript code. • Your browser has a JavaScript engine - the program that runs your code. • The Parser reads it and breaks it into tokens (small code pieces). • These tokens form an AST (Abstract Syntax Tree) -  a diagram that shows how your code is arranged • If something’s wrong, the parser stops and shows a syntax error. 🔹 𝗦𝘁𝗲𝗽 𝟮: 𝗜𝗻𝘁𝗲𝗿𝗽𝗿𝗲𝘁𝗮𝘁𝗶𝗼𝗻 (𝗘𝘅𝗲𝗰𝘂𝘁𝗶𝗼𝗻 𝗕𝗲𝗴𝗶𝗻𝘀) • The Interpreter turns the AST into Bytecode (instructions the engine can run). • The Bytecode runs inside the engine, not directly on the CPU. • The program starts running after this step. • The engine tracks which parts run often and what data types are used. 🔹 𝗦𝘁𝗲𝗽 𝟯: 𝗝𝗜𝗧 𝗖𝗼𝗺𝗽𝗶𝗹𝗮𝘁𝗶𝗼𝗻 (𝗢𝗽𝘁𝗶𝗺𝗶𝘇𝗮𝘁𝗶𝗼𝗻) • The engine finds hot code (functions or loops that run many times). • It sends them to the JIT (Just-In-Time) Compiler, which turns hot code into faster Machine Code during execution. • This Machine Code runs directly on the CPU. • The result - same code, now runs much faster. 🔹 𝗦𝘁𝗲𝗽 𝟰: 𝗔𝗱𝗮𝗽𝘁𝗶𝘃𝗲 𝗢𝗽𝘁𝗶𝗺𝗶𝘇𝗮𝘁𝗶𝗼𝗻 (𝗦𝘁𝗮𝘆 𝗙𝗹𝗲𝘅𝗶𝗯𝗹𝗲) • The engine constantly checks how code behaves. • If types or logic change, it re-optimizes the code for the new pattern. • This adaptive process keeps JavaScript dynamic and efficient. 🔹 𝗦𝘁𝗲𝗽 𝟱: 𝗚𝗮𝗿𝗯𝗮𝗴𝗲 𝗖𝗼𝗹𝗹𝗲𝗰𝘁𝗶𝗼𝗻 (𝗖𝗹𝗲𝗮𝗻 𝘁𝗵𝗲 𝗠𝗲𝗺𝗼𝗿𝘆) • When code or data is no longer needed, it’s removed automatically. • The Garbage Collector (GC) finds and clears unused memory. • This keeps memory light and your app smooth. 🔄 𝗙𝘂𝗹𝗹 𝗙𝗹𝗼𝘄: Parsing → Interpretation → JIT Compilation → Adaptive Optimization → Garbage Collection Follow Saurav Kumar for more easy-to-understand Frontend insight. ✨ Would love to know your thoughts 👇 #JavaScript #FrontendDevelopment #WebDevelopment   #JSEngine #ReactJS #Coding #Programming

This article by Sumit Saha explores the concept of multi-threading in Node.js using worker threads, a significant approach for handling concurrent operations. I found it interesting that while JavaScript is traditionally single-threaded, implementing worker threads can greatly enhance performance for computationally intensive tasks. What strategies have you used to optimize performance in your Node.js applications? Read more: https://lnkd.in/dpVdJir4

Ever wondered why JavaScript, a single-threaded language, can handle thousands of operations concurrently without getting blocked? 🤔 The secret is the Event Loop! The Event Loop is the core mechanism that allows JavaScript to perform non-blocking I/O operations. It's the heart of JS's asynchronous programming model, and understanding it is a game-changer for any developer. Here’s a simple breakdown of how it works: 🔹 **Call Stack:** This is where your synchronous code is executed. It's a "last in, first out" stack. When you call a function, it's pushed to the stack, and when it returns, it's popped off. 🔹 **Web APIs / C++ APIs (in Node.js):** When you encounter an asynchronous operation (like `setTimeout`, a network request, or a database query), it's handed off to these browser/Node.js APIs. This frees up the Call Stack to continue executing the rest of your synchronous code. 🔹 **Callback Queue (or Task Queue):** Once the async operation is complete, its associated callback function is placed into this queue, waiting for its turn to be executed. 🔹 **The Event Loop:** This is the hero of the story. Its one and only job is to constantly monitor if the Call Stack is empty. If it is, it takes the first item from the Callback Queue and pushes it onto the Call Stack for execution. This simple yet powerful model prevents long-running operations from blocking the main thread, ensuring a smooth UI in browsers and high-throughput servers in Node.js. Mastering it is key to writing efficient and scalable JavaScript. #JavaScript #EventLoop #NodeJS #WebDevelopment #Programming #Developer #Asynchronous #Concurrency #SoftwareEngineering #Coding #TechExplained #LearnToCode

🔥 𝐌𝐚𝐬𝐭𝐞𝐫 𝐭𝐡𝐞 𝐂𝐨𝐫𝐞 𝐉𝐚𝐯𝐚𝐒𝐜𝐫𝐢𝐩𝐭 𝐂𝐨𝐧𝐜𝐞𝐩𝐭𝐬 𝐄𝐯𝐞𝐫𝐲 𝐃𝐞𝐯𝐞𝐥𝐨𝐩𝐞𝐫 𝐒𝐡𝐨𝐮𝐥𝐝 𝐊𝐧𝐨𝐰 If you want to become truly confident in JS — not just copy code from tutorials — you must deeply understand how the language actually works under the hood. Here’s a quick roadmap of core concepts to focus on 👇 1️⃣ 𝐂𝐥𝐨𝐬𝐮𝐫𝐞𝐬 – Functions that can access variables from their outer scope even after that scope has finished executing. Use cases: Data privacy, currying, and maintaining state. 2️⃣ 𝐏𝐫𝐨𝐦𝐢𝐬𝐞𝐬 & 𝐀𝐬𝐲𝐧𝐜/𝐀𝐰𝐚𝐢𝐭 – Handle asynchronous tasks like API calls or timers without blocking the main thread. Understand promise chaining and error handling for cleaner async code. 3️⃣ 𝐓𝐡𝐞 '𝐭𝐡𝐢𝐬' 𝐊𝐞𝐲𝐰𝐨𝐫𝐝 – Points to the execution context of a function. How ‘this’ behaves changes with function types, strict mode, and binding methods. 4️⃣ 𝐄𝐯𝐞𝐧𝐭 𝐋𝐨𝐨𝐩 – The heart of JavaScript concurrency. Helps JS handle asynchronous tasks by managing the call stack and the callback queue. 5️⃣ 𝐇𝐨𝐢𝐬𝐭𝐢𝐧𝐠 – JavaScript moves declarations (not initializations!) to the top of their scope. Understand how `var`, `let` and `const` differ. 6️⃣ 𝐀𝐫𝐫𝐨𝐰 𝐅𝐮𝐧𝐜𝐭𝐢𝐨𝐧𝐬 – Shorter syntax for anonymous functions that *don’t* bind their own ‘this’. Great for callbacks and when lexical ‘this’ is needed. 7️⃣ 𝐃𝐞𝐬𝐭𝐫𝐮𝐜𝐭𝐮𝐫𝐢𝐧𝐠 – Extract values from arrays or objects easily. Makes code cleaner and more readable. 8️⃣ 𝐒𝐩𝐫𝐞𝐚𝐝 & 𝐑𝐞𝐬𝐭 𝐎𝐩𝐞𝐫𝐚𝐭𝐨𝐫𝐬 – Spread expands, Rest collects. Used for cloning arrays/objects or handling dynamic arguments. 9️⃣ 𝐌𝐚𝐩(), 𝐅𝐢𝐥𝐭𝐞𝐫() & 𝐑𝐞𝐝𝐮𝐜𝐞() – Power trio for array transformations. Learn their differences for clean, functional-style coding. 1️⃣0️⃣ 𝐂𝐚𝐥𝐥, 𝐀𝐩𝐩𝐥𝐲 & 𝐁𝐢𝐧𝐝 – Control how functions are invoked and which ‘this’ they use. Critical for advanced JS patterns and reusability. 💡 Pro Tip: Don’t just read about them — open the console, try small examples, and experiment. #SDET #Developer #JavaScript #CSS #HTML #WebDev #CareerGrowth

𝐀𝐥𝐥 𝐚𝐛𝐨𝐮𝐭 𝐡𝐨𝐰 𝐄𝐯𝐞𝐧𝐭 𝐋𝐨𝐨𝐩 𝐰𝐨𝐫𝐤𝐬 𝐢𝐧𝐭𝐞𝐫𝐧𝐚𝐥𝐥𝐲 𝐈𝐧 𝐉𝐚𝐯𝐚𝐒𝐜𝐫𝐢𝐩𝐭 !! Understanding how JavaScript’s event loop works, especially with async/await, is a game changer for any developer. JavaScript doesn’t just run code line by line when async functions are involved. Instead, it uses something called the event loop, which manages different queues to decide what runs when. There are Microtasks (like promises and await) and Macrotasks (like setTimeout), and Microtasks always get priority. This means even when you use await, JavaScript pauses only inside that function but continues running other code outside it. That’s why sometimes console logs appear in unexpected orders! Grasping this helps you write better asynchronous code, avoid tricky bugs, and build smoother apps. Keep digging into these concepts — it’s worth it! In this post, I’m sharing everything you need to know about JavaScript’s event loop — explained in simple words. To make it even easier, I’ve created a set of slides that break down the concept step-by-step. Follow Gourav Roy for more such amazing content !! 𝐂𝐨𝐧𝐧𝐞𝐜𝐭 𝐨𝐧 𝐓𝐨𝐩𝐦𝐚𝐭𝐞 - https://lnkd.in/gyGxA7ut 𝐂𝐨𝐧𝐧𝐞𝐜𝐭 𝐨𝐧 𝐈𝐧𝐬𝐭𝐚𝐠𝐫𝐚𝐦 - https://lnkd.in/djMF2k3Q #JavaScript #EventLoop #AsyncAwait #WebDevelopment #CodingTips #Java

Ever heard of the “Error-First Callback” pattern in Node.js? It’s one of those fundamental concepts that, once you really understand it, can dramatically boost your confidence in handling asynchronous code — especially when diving into older Node.js codebases or working on tooling that doesn’t quite use Promises or async/await yet. Here’s the gist: Error-First Callbacks are a convention where the first argument of a callback function is reserved for an error object (if any), and subsequent arguments carry successful results. This simple pattern helps keep asynchronous code clean and predictable. Why should you care in 2024? Because even though async/await and Promises have mostly taken over (thankfully!), Node.js core modules, some legacy code, and many libraries still rely on Error-First Callbacks. Mastering this pattern helps you read, refactor, debug, or wrap old APIs comfortably — an often overlooked skill! Here’s a classic example: function readFile(filename, callback) { fs.readFile(filename, 'utf8', (err, data) => { if (err) return callback(err); callback(null, data); }); } readFile('example.txt', (error, content) => { if (error) { console.error('Oops, something went wrong:', error.message); } else { console.log('File content:', content); } }); Notice how the callback checks if error is truthy first. If so, it handles the error — or passes it up the chain — before processing results. This pattern avoids “callback hell” confusion, making your async code more robust and less error-prone. Pro tip: When creating your own async utilities, adopt this pattern if you want other developers to integrate smoothly with your code, especially if you're targeting environments or libraries that haven’t fully embraced Promises. In today’s world, mixing old and new async approaches is common. Embrace Error-First Callbacks as a bridge between legacy and modern Node.js — it’s a tiny skill with a big impact. #NodeJS #JavaScript #AsyncProgramming #ErrorHandling #SoftwareEngineering #CodingTips #TechFundamentals #DeveloperLife

8 JavaScript topics that actually matter Been coding for a while now, these keep coming up: → Closures Functions that remember their context. Used everywhere in React hooks and callbacks. → Promises & Async/Await Writing code that waits without freezing. Essential for API calls. → Array Methods map(), filter(), reduce(). Clean data manipulation. → Event Loop How JavaScript handles async ops. Makes everything click once you get it. → Destructuring Cleaner way to pull values from objects and arrays. Saves a lot of lines. → Spread/Rest Operators Copy arrays, merge objects, handle function params. Super useful. → Prototypes & Inheritance How objects actually work under the hood. Important for interviews. → Module Systems Import/export between files. Keeps code organized. These aren't flashy. But knowing them makes everything easier. What topic gave you the most trouble when learning JS? #JavaScript #Coding #WebDevelopment #100DaysOfCode #LearnToCode #FrontendDevelopment #MERNStack #DeveloperTips