Async JavaScript: Boost UI Speed with Async/Await

JavaScript Fundamentals – How the Event Loop Works 🔄 JavaScript is single-threaded. So a common question is: 👉 How does JS handle async tasks like setTimeout, promises, or API calls? The answer is the Event Loop. When JavaScript runs, it manages code using three main parts: 1️⃣ Call Stack This is where synchronous code runs. Functions are pushed in, executed, and popped out. 2️⃣ Web APIs Async tasks like setTimeout, DOM events, and fetch are handled here by the browser. 3️⃣ Callback / Microtask Queue • Callbacks from setTimeout go to the Callback Queue • Promises (then, catch) go to the Microtask Queue ⚠️ Microtask Queue has higher priority than Callback Queue. What does the Event Loop do? The Event Loop constantly checks: ➡️ Is the Call Stack empty? ➡️ If yes, push tasks from the queues to the stack Order of execution: • Call Stack • Microtask Queue • Callback Queue That’s why promises run before setTimeout, even with 0ms. Why does this matter? Understanding the Event Loop helps you: • Debug async bugs • Avoid UI blocking • Write better async code • Answer interview questions with confidence Strong JS fundamentals = better frontend developer 🚀 #JavaScript #FrontendDevelopment #WebDevelopment #LearningInPublic

Recently, I revisited one JavaScript concept that has confused me more than once: the this keyword 🤯 I knew what this was supposed to represent, but in real projects, it often didn’t behave the way I expected. Sometimes it worked ✅, sometimes it returned undefined ❌, and sometimes it pointed somewhere completely unexpected 😅 While digging deeper, I finally understood how call, apply, and bind actually give us control over this 🔧 Here’s what clicked for me 👇 1️⃣ call() lets you invoke a function immediately and explicitly tell it what this should be. 2️⃣ apply() does the same thing, but expects the arguments as an array 📦 3️⃣ bind() doesn’t execute the function right away — instead, it returns a new function where this is permanently fixed 🔒 Once I understood this difference, a lot of JavaScript behavior started to feel predictable instead of magical ✨➡️📐 To make sure I really internalized it, I wrote a short blog using a simple real-world example and practical code snippets 🧠💻 Sharing it here in case it helps someone else who’s wrestling with this 👇 🔗 https://lnkd.in/gDXMqP8m Hitesh Choudhary Piyush Garg Chai Aur Code Akshay Saini 🚀 #JavaScript #LearningInPublic #WebDevelopment #CallApplyBind #ThisKeyword #Frontend

JavaScript in production isn’t about tricks — it’s about avoiding silent bugs. New Substack article is live ✍️ “𝐉𝐚𝐯𝐚𝐒𝐜𝐫𝐢𝐩𝐭 𝐜𝐨𝐧𝐜𝐞𝐩𝐭𝐬 𝐭𝐡𝐚𝐭 𝐚𝐜𝐭𝐮𝐚𝐥𝐥𝐲 𝐦𝐚𝐭𝐭𝐞𝐫 𝐢𝐧 𝐩𝐫𝐨𝐝𝐮𝐜𝐭𝐢𝐨𝐧” In this piece, I cover: 1️⃣ Values vs references (root of many UI bugs) 2️⃣ Closures and why they show up everywhere 3️⃣ The event loop and why UIs freeze 4️⃣ Async/await + real-world error handling 5️⃣ Practical concepts like truthy/falsy, this, immutability, debounce/throttle 🔗 Read it here: https://lnkd.in/gjvmnZgH Feel free to comment and share which JS concept helped you most in real projects 👇 #JavaScript #FrontendDevelopment #WebDevelopment #SoftwareEngineering #FrontendEngineering

How JavaScript Actually Runs Behind the Scenes Most of us write JavaScript every day. But real confidence comes when you understand how JavaScript executes, not just how it looks. JavaScript runs in two main phases inside the JS engine: 1️⃣ Memory Creation Phase Variables are allocated memory and initialized with undefined Functions are stored entirely in memory This is why hoisting happens 2️⃣ Code Execution Phase Code runs line by line Values are assigned to variables Functions are executed using the Call Stack Behind the scenes, the engine manages: Call Stack → Executes functions one at a time Memory Heap → Stores objects and functions Web APIs → Handles async tasks like setTimeout, fetch, DOM events Callback Queue & Microtask Queue → Holds async callbacks Event Loop → Decides when async code moves back to the Call Stack That is why: setTimeout(fn, 0) does not run immediately Promises run before setTimeout Blocking the call stack freezes the UI Understanding this changes how you: Debug async bugs Write better performance code Reason about Angular, React, and frontend frameworks JavaScript feels simple on the surface. Its power comes from what happens underneath. If you are a frontend developer, learning JS internals is not optional anymore. What concept confused you the most when you first learned JavaScript? #JavaScript #FrontendDevelopment #WebDevelopment #NamasteJavaScript #Angular #React #SoftwareEngineering

So, you're building projects with JavaScript - and that's awesome. But, let's get real, do you really understand how the "this" keyword works? It's tricky. Its value is all about how a function is called, not where it's defined - that's the key. You see, context is everything here. And, honestly, it's not that hard once you wrap your head around it. The thing is, "this" behaves differently in various contexts - and that's what trips people up. For instance, when you're working with object literals, the "this" keyword refers to the object itself - makes sense, right? But, when you're dealing with function calls, it's a whole different story - thethis keyword can refer to the global object, or even null, depending on how the function is invoked. So, it's essential to understand these nuances to avoid common mistakes. Like, have you ever tried to access a property using "this", only to find out it's undefined? Yeah, that's frustrating. Anyway, if you're just starting out with JavaScript, or revisiting the basics, this post is for you. You'll learn whatthis means in JavaScript, how it behaves in different contexts, and some common pitfalls to watch out for. It's all about mastering the "this" keyword - and trust me, it's worth it. Check out this deep dive: https://lnkd.in/g-tn9CXj #JavaScript #Coding #WebDevelopment

Most people use JavaScript daily, yet very few truly understand how it operates behind the scenes. One critical concept that is often overlooked is the Event Loop, particularly the distinction between microtasks and macrotasks. JavaScript is single-threaded, so how does it manage asynchronous code without freezing? The answer lies in the Event Loop. It's important to note that not all asynchronous tasks are treated equally: - Microtasks: - Promise.then() - async/await - queueMicrotask() - Macrotasks: - setTimeout - setInterval - DOM events - I/O callbacks Microtasks always execute before macrotasks. For example: setTimeout(() => console.log("timeout"), 0); Promise.resolve().then(() => console.log("promise")); The output will be: promise timeout This occurs even though the timeout is set to 0. Understanding this distinction is crucial for real projects, as it can lead to: - Unexpected UI freezes - Race conditions in asynchronous logic - Bugs that only surface in production - Poor performance in large React and Node.js applications Frameworks like React, Next.js, and Node.js rely heavily on this behavior. Without a solid grasp of the Event Loop, debugging asynchronous issues can become a guessing game. This topic is not merely theoretical; it directly affects performance, reliability, and scalability. Many tutorials overlook it, yet industry code depends on this knowledge. If you aim to advance your JavaScript skills, mastering this concept is essential.

Interviewer:- Explain Hoisting in Javascript. Answer:- JavaScript Hoisting refers to the process whereby the interpreter appears to move the declaration of functions, variables, classes, or imports to the top of their scope, prior to execution of the code.(MDN Defination) Hoisting is a core JavaScript behavior where declarations are processed before code execution. This means the JS engine scans the code first and allocates memory for variables and functions. 🔹 var Hoisting Variables declared with var are hoisted and initialized with undefined. You can access them before declaration, but the value won’t be available yet. 🔹 let & const Hoisting These are also hoisted, but not initialized. They exist in the Temporal Dead Zone (TDZ) until the declaration line is executed. Accessing them early throws a ReferenceError. 🔹 Function Hoisting Function declarations are fully hoisted, including their definitions, so they can be called before being defined. Function expressions and arrow functions follow variable hoisting rules. 🔹Arrow Function Hoisting in JavaScript Arrow functions are not hoisted like function declarations. Their hoisting behavior depends on how they are defined. 1. Arrow Functions with var The variable is hoisted and initialized as undefined, but the function is not. Calling it before assignment results in a TypeError. 2. Arrow Functions with let or const They are hoisted but remain in the Temporal Dead Zone (TDZ). Accessing them before initialization throws a ReferenceError. 🔹 Key Difference Unlike normal function declarations, arrow functions cannot be called before they are defined. 📌 Best Practice Always define arrow functions before using them to avoid unexpected runtime errors. 📌 Why it matters? Understanding hoisting helps prevent runtime errors, improves debugging, and leads to more predictable and maintainable JavaScript code. #JavaScript #JS #Hoisting #WebDevelopment #FrontendDevelopment #Frontend #Programming #Coding #Developer #SoftwareDevelopment #LearningToCode #Tech #CodeNewbie #100DaysOfCode #WebDev #ReactJS #NodeJS

🧠 JavaScript – Scope, Hoisting & this Understanding How JavaScript Works Internally To write better JavaScript, it’s not enough to know what to write we must understand how JavaScript executes code behind the scenes. This is where scope, hoisting, and this become important. 🔹 Scope in JavaScript Scope defines where a variable can be accessed. 🌍 Global Scope Variables declared outside functions or blocks. let appName = "MyApp"; function showName() { console.log(appName); } 👉 Accessible everywhere in the program. 🏠 Local (Function) Scope Variables declared inside a function. function greet() { let message = "Hello"; console.log(message); } 👉 Cannot be accessed outside the function. 📦 Block Scope Variables declared using let and const inside {}. if (true) { let count = 5; } 👉 count is not accessible outside the block. 🔹 Hoisting (Important Concept) Hoisting means JavaScript moves declarations to the top before execution. console.log(a); var a = 10; 👉 Output: undefined (The declaration is hoisted, not the value.) let and const with Hoisting console.log(b); let b = 5; 👉 This causes an error. Why? let and const are hoisted But not initialized (Temporal Dead Zone) 🔹 The this Keyword this refers to the object that is currently using the function. In a Regular Function console.log(this); 👉 Refers to the global object (window in browsers). Inside an Object let user = { name: "Alex", greet() { console.log(this.name); } }; 👉 this refers to the user object. Arrow Functions & this let user = { name: "Alex", greet: () => { console.log(this.name); } }; 👉 Arrow functions do not have their own this. 🧠 Simple Way to Remember Scope → where variables live Hoisting → how JS reads code this → who owns the function Understanding these prevents confusing bugs. ✅ Why This Matters Helps write predictable code Avoids scope-related errors Makes frameworks easier to understand Often asked in interviews If you understand this, you’re thinking like a real JavaScript developer. . . #JavaScript #WebDevelopment #ProgrammingBasics #LearningInPublic #FrontendDevelopment #FullStackJourney

So, you're building something with JavaScript - and it's getting big. One file just isn't cutting it anymore. JavaScript module system to the rescue. It's like a librarian for your code, helping you keep things tidy and organized. You can break up your code into smaller, reusable files - and control what's visible, what's not. Only load what you need, when you need it. Modern JavaScript is all about ES Modules (ESM), by the way. They're the way to go. Here's the lowdown: - You can have named exports and imports, which is super useful. - Default exports and imports are a thing too. - And then there's aliasing - which helps you avoid naming conflicts, like when you're working with multiple modules that have the same variable names. - Namespace imports are another cool feature - you can import all values from a module as an object. - Combined imports are also possible - you can import both default and named exports at the same time. - And let's not forget dynamic imports - which load modules at runtime, like when you need to load a big library, but only when the user interacts with a certain part of your app. A JavaScript module is basically a file with its own scope - it's like a little box that can export variables, functions, or classes, and import values from other modules. To use modules in the browser, just add type="module" to your script tag. Easy peasy. You can export multiple values from one file, no problem. Just remember, when you import them, the names have to match. And you can only have one default export per module - but you can import it with any name you want, which is nice. Aliasing is also super helpful - it lets you rename imports to avoid conflicts. Dynamic imports are pretty cool too - they load modules at runtime, which is great for code splitting, lazy loading, and performance optimization. They always return a Promise, so you can use Promise.all to load multiple modules in parallel. So, what's the big deal about the JavaScript module system? It makes your code easier to maintain, more scalable, and better organized - which is a win-win-win. Check out this article for more info: https://lnkd.in/gBPF8NUr #JavaScript #ESModules #CodeOrganization

JavaScript is single-threaded, yet it handles: ✅ API calls ✅ Timers ✅ User events ✅ UI updates all without blocking the main thread. 🤯 In this post, I break down: 🔹 Promises vs async/await 🔹 How the Event Loop really works 🔹 Microtasks vs Callback Queue 🔹 Common mistakes developers make 🔹 Real-world examples you can relate to If async JavaScript ever felt “magical” or confusing, this one is for you 👇 📖 Read here: https://lnkd.in/eiNxr9Hb #JavaScript #AsyncAwait #Promises #EventLoop #WebDevelopment #Frontend #Programming #LearnToCode #ReactJS #NodeJS