Ever been confused by this in JavaScript?.You're not alone. It behaves differently in functions, objects, classes, arrow functions,even the DOM. I broke it all down clearly (with examples). Post link in the comments.

Join millions who have switched to Grok.

I rebuilt React’s useEffect hook from scratch. Tracked deps, Handled cleanup, Simulated React’s mind. Learn why useEffect(() => {}, []) runs twice in dev, how StrictMode works, and how React decides when to re-run your effect. 👇 Full breakdown in the comments.

I rebuilt React’s component model in my head ,. from class components.to hooks. to how lifecycle actually works under the hood. no magic. just objects, effects, and a ton of learning. you don’t really understand React. until you know what it was before . breakdown in the comment.

I rebuilt React’s <Link> from scratch . - no router .- no dependencies . just JS, the History API,. - no reloads .- state stays .- URL updates instantly. why?. because you don’t really understand something,. until you build it yourself. breakdown in the comment.

7️⃣ Difference Between app.use() & app.all(). ✅ app.use(path, middleware): Runs middleware for all methods (GET, POST, etc.). ✅ app.all(path, handler): Runs for all methods but only on that path. #NodeJS #ExpressJS #Backend #100DaysOfCode

6️⃣ How Express Handles Requests Behind the Scenes. 🔹 Receives request.🔹 Matches the route & method.🔹 Executes middleware (app.use).🔹 Passes request to the matching route handler.🔹 Executes route handlers step by step (next()).🔹 Sends response.

5️⃣ What is Middleware & Why Do We Need It?.Middleware functions sit between the request and response, allowing authentication, logging, validation, error handling, and more!

4️⃣ app.use() with Multiple Handlers.We can attach multiple route handlers at once using app.use().

3️⃣ Handling Errors in Middleware.Use next(err) to send errors to an error-handling middleware.

🔹 next() moves the request to the next handler. 2️⃣ What if next() is missing?.Without next(), the request stops at the first handler. The order matters !

🚀Route Handlers & Middleware in Express.js. 1️⃣ Multiple Route Handlers – Play with Code!.Instead of writing everything in one function, we can split logic into multiple handlers for cleaner, modular code.

🔹 Networking tasks don’t use the thread pool; they rely on efficient OS mechanisms like epoll & kqueue. 🔹 Streams, Buffers, and Pipes make data handling efficient. #NodeJS #JavaScript #Backend.

🔟 Key Takeaways:. 🔹 Node.js is single-threaded for sync code but uses multiple threads for async tasks. 🔹 The libuv thread pool handles tasks like file system operations & crypto.

9️⃣ Pipes: Simplifying Stream Operations. Pipes connect readable streams to writable streams, making it easy to transfer data. This method is faster & memory-efficient! 🚀.

8️⃣ Buffers: Handling Binary Data. Buffers store raw binary data and are commonly used in:.✅ File system operations.✅ Network communications.✅ Streams. Buffers help Node.js process large data efficiently! ⚡.

7️⃣ Streams allow reading/writing data in chunks, reducing memory usage. Types of Streams:.✅ Readable – Read data (eg fs.createReadStream).✅ Writable – Write data (eg fs.createWriteStream).✅ Duplex – Both read & write (eg TCP socket).✅ Transform – Modify data (eg compression).