TechNetExperts’ Post

Assalam o Alaikum, Deep dive: JavaScript Modules (import / export) and project structure. Problem: messy codebases where functions and utilities are scattered across files. Solution: small, focused modules and predictable import/export patterns. In this lesson I demonstrate: • Named exports for utilities (clean, tree-shakable functions).   • Default exports for single responsibility classes (Calculator, StorageHelper).   • Mixed exports and import aliasing (useful for readable names).   • Building an API client module and centralizing headers/auth.   • Practical file structure and tips to avoid circular dependencies. If you deliver front-end features or maintain shared libraries, this will help you ship cleaner, testable code and reduce bundle size. Watch: https://lnkd.in/dw8Bh52W #JavaScript #Modules #ImportExport #CodeOrganization #Frontend #BestPractices #DeveloperMinds

Ever changed an @Input() object… and nothing updated? Angular isn’t broken — your object reference didn’t change. I wrote a short breakdown explaining why this happens and how to fix it properly. 🔗 Read here: https://lnkd.in/d7vz_Jd6 #Angular #WebDevelopment #Frontend #SoftwareEngineering #JavaScript #ChangeDetection

Stop using await as a "Pause" button for everything. 🛑 The image below visualizes a common performance killer I see in JavaScript PRs: The "Waterfall" effect. Look at the code on the left. We are waiting for posts to finish fetching before we even start fetching settings. // ❌ The Waterfall (Slow) const user = await fetchUser(id); const posts = await fetchPosts(user.id); // Waits... const settings = await fetchSettings(user.id); // Waits more... The Problem? posts and settings don't depend on each other. By awaiting them sequentially, you are unnecessarily blocking execution and doubling the wait time for your user. The Fix? Identify independent data and fetch it in parallel using Concurrency. // ✅ The Parallel Way (Fast) const user = await fetchUser(id); // Fire both requests at the same time const [posts, settings] = await Promise.all([ fetchPosts(user.id), fetchSettings(user.id) ]); Why this matters: UX: Your application loads significantly faster. Efficiency: You utilize the browser's ability to handle concurrent network requests. The Debate: Some seniors prefer Promise.allSettled over Promise.all for better error handling in production (so one failed request doesn't break the entire page). 👇 Are you Team Promise.all for speed, or Team Promise.allSettled for safety? Let me know your preference in the comments! #JavaScript #WebDevelopment #SoftwareEngineering #CodingTips #Performance #FullStack

A lot of developers use const and let without really understanding the difference. They both declare block-scoped variables, but they are not the same thing. In a simple sentence: - let: value can be reassigned - const: value cannot be reassigned This is just it at the highest level. Example: let count = 5; count = 10; // This is allowed const total = 20; total = 30; // This throws an Error Note: If you try to reassign a const, JavaScript throws an error. Also, "const" does not mean immutable... It means the reference cannot change, not the content. Example: const user = { name: "John" }; user.name = "Jane"; // This is allowed user.age = 25; // This is allowed You can modify properties inside an object declared with const. You just can’t reassign the entire object. Tip: - Use "const" by default. - Only use "let" when: - You know the variable will be reassigned - You’re dealing with counters or dynamic values

𝗧𝗵𝗲 𝗥𝗲𝗮𝗹𝗺𝘀 𝗔𝗣𝗜: 𝗜𝘀𝗼𝗹𝗮𝘁𝗲𝗱 𝗘𝘅𝗲𝗰𝘂𝘁𝗶𝗼𝗻 𝗖𝗼𝗻𝘁𝗲𝘅𝘁𝘀 The Realms API is a JavaScript feature that lets you create isolated execution contexts. This helps you run code securely and independently. You can use it to execute untrusted code or manage different library versions. The Realms API solves problems that developers had with security. Before, they used things like: - IIFE: provides some encapsulation but does not prevent global state interference - Web Workers: offers threading but lacks direct DOM access - iframing: effective for isolation but can introduce complexity You can create a realm using the Realm constructor. Each realm has its own global object. You can run code within a realm: ``` is not allowed, using plain text instead const realm = new Realm() realm.evaluate(() => { console.log("Hello from inside the realm!") return 42 }) Realms can import and export functions and objects. This allows for complex interactions while maintaining isolation. You can also shadow global objects by introducing custom properties. When executing asynchronous functions in realms, pay attention to promises. Realms can communicate through structured clones. This technique allows for serialization of objects that can be sent between realms. Realms are useful for creating code execution sandboxes. They help prevent versioning conflicts and allow multiple library versions to coexist. To use Realms efficiently, consider: - Batching: execute multiple isolated operations in a single realm - Garbage Collection: clean up realms correctly - Scope and Context: remember that global variables in one realm do not exist in another - Promise Handling: handle promises correctly across realms - Resource Management: manage realm creation and destruction Source: https://lnkd.in/gimfmqBt

𝐂++ 𝐚𝐧𝐝 𝐉𝐚𝐯𝐚 𝐝𝐞𝐯𝐬 𝐠𝐞𝐭 𝐛𝐮𝐢𝐥𝐭-𝐢𝐧 𝐜𝐨𝐩𝐲 𝐜𝐨𝐧𝐬𝐭𝐫𝐮𝐜𝐭𝐨𝐫𝐬. 𝐉𝐚𝐯𝐚𝐒𝐜𝐫𝐢𝐩𝐭 𝐝𝐞𝐯𝐬 𝐠𝐞𝐭 𝐭𝐫𝐮𝐬𝐭 𝐢𝐬𝐬𝐮𝐞𝐬. 🚩 Let’s talk about constructors—the factory blueprints for our objects. In JavaScript, setting up a constructor is pretty straightforward. You have your 𝐍𝐨𝐧-𝐏𝐚𝐫𝐚𝐦𝐞𝐭𝐞𝐫𝐢𝐳𝐞𝐝 constructors (handing out default values like participation trophies) and your 𝐏𝐚𝐫𝐚𝐦𝐞𝐭𝐞𝐫𝐢𝐳𝐞𝐝 constructors (passing in actual, useful data). But then you try to clone an object. JavaScript looks at you, shrugs, and says, "Figure it out yourself." Unlike other languages, JS doesn't have a built-in copy constructor. If you lazily type `const newObj = oldObj;`, you didn't create a copy. You just created a new reference to the exact same memory location. The moment you change `newObj`, you mutate `oldObj`, your UI breaks, your tests fail, and your PM is asking why the dashboard is upside down. To truly copy an instance of a class, you have to build your own `copy()` method to explicitly return a `new` instance with the cloned data. Stop trusting the assignment operator (`=`). It is lying to you. 𝐂𝐨𝐧𝐟𝐞𝐬𝐬𝐢𝐨𝐧 𝐭𝐢𝐦𝐞: 𝐇𝐨𝐰 𝐦𝐚𝐧𝐲 𝐩𝐫𝐨𝐝𝐮𝐜𝐭𝐢𝐨𝐧 𝐛𝐮𝐠𝐬 𝐡𝐚𝐯𝐞 𝐲𝐨𝐮 𝐜𝐚𝐮𝐬𝐞𝐝 𝐛𝐲 𝐚𝐜𝐜𝐢𝐝𝐞𝐧𝐭𝐚𝐥𝐥𝐲 𝐦𝐮𝐭𝐚𝐭𝐢𝐧𝐠 𝐚 𝐫𝐞𝐟𝐞𝐫𝐞𝐧𝐜𝐞𝐝 𝐨𝐛𝐣𝐞𝐜𝐭 𝐢𝐧𝐬𝐭𝐞𝐚𝐝 𝐨𝐟 𝐚𝐜𝐭𝐮𝐚𝐥𝐥𝐲 𝐜𝐨𝐩𝐲𝐢𝐧𝐠 𝐢𝐭? 𝐋𝐞𝐭'𝐬 𝐡𝐞𝐚𝐫 𝐭𝐡𝐞 𝐡𝐨𝐫𝐫𝐨𝐫 𝐬𝐭𝐨𝐫𝐢𝐞𝐬 𝐢𝐧 𝐭𝐡𝐞 𝐜𝐨𝐦𝐦𝐞𝐧𝐭𝐬. 👇 #JavaScript #WebDevelopment #SoftwareEngineering #MERNStack #CodingHumor #DeveloperLife #TechTips #Programming

𝗧𝗵𝗲 𝗥𝗲𝗮𝗹𝗺𝘀 𝗔𝗣𝗜: 𝗜𝘀𝗼𝗹𝗮𝘁𝗲𝗱 𝗘𝘅𝗲𝗰𝘂𝘁𝗶𝗼𝗻 𝗖𝗼𝗻𝘁𝗲𝘅𝘁𝘀 The Realms API is a JavaScript feature that lets you create isolated execution contexts. This helps you run code securely and independently. You can use it to execute untrusted code or manage different library versions. The Realms API solves problems that developers had with other methods like IIFE, Web Workers, and iframing. These methods had limitations, such as: - IIFE: provides basic encapsulation but does not prevent global state interference - Web Workers: offers threading but lacks direct DOM access - iframing: effective for isolation but introduces complexity and same-origin policy issues You can create a realm using the Realm constructor. Each realm has its own global object, which means separate global variables and functions. You can run code within a realm and import/export functions and objects between realms. Realms can also shadow global objects by introducing custom properties. This helps prevent conflicts or provide mock implementations. When executing asynchronous functions in realms, you need to handle promises carefully. The Realms API is useful for creating code execution sandboxes and preventing versioning conflicts in large applications. However, it requires careful consideration of performance, optimizations, and debugging. To get the most out of the Realms API, consider: - Batching: execute multiple isolated operations in a single realm - Garbage Collection: clean up realms correctly to avoid memory issues - Scope and Context: remember that global variables in one realm do not exist in another - Promise Handling: handle promises correctly across realms to avoid errors - Resource Management: manage realm creation and destruction to avoid memory leaks Source: https://lnkd.in/gdHxmZc3

👉 First, What Is a Closure? A closure happens when: 1️⃣A function remembers the variables from its outer (lexical) scope even after the outer function has finished executing. 2️⃣A function keeps access to the environment in which it was created. 👉JavaScript variables can belong to: The local scope The global scope Global variables can be made local (private) with closures. Closures make it possible for a function to have "private" variables. A closure is created when a function remembers the variables from its outer scope, even after the outer function has finished executing. Example: - function outer() {   let count = 0;   return function inner() {    count++;    console.log(count);   }; } const counter = outer(); counter(); // 1 counter(); // 2 Even though outer() has finished running, the inner() function still remembers count. That’s a closure. What’s Actually Happening? When outer() executes: • A new execution context is created • count is stored in memory • inner() is returned Because inner() still references count, JavaScript keeps it alive in memory. The function “closes over” its lexical scope. 🙎♂️Where Closures Are Used in Real Applications❓ ✔ Data privacy ✔ Creating private variables ✔ Factory functions ✔ Event handlers ✔ Maintaining state Many advanced patterns in JavaScript rely heavily on closures.

Theory: "setTimeout callbacks execute after the Call Stack is empty." Practice: I'd never actually put numbers to it until today. ```javascript const start = Date.now(); const delay = (label, ms) =>   console.log(`${label} delayed by ${Date.now() - start - ms}ms`); setTimeout(delay, 0, '0ms', 0); setTimeout(delay, 1, '1ms', 1); setTimeout(delay, 100, '100ms', 100); setTimeout(delay, 300, '300ms', 300); setTimeout(delay, 600, '600ms', 600); for (let i = 0; i < 100000000; i++); // ~100ms blocking work ``` Output: ``` 0ms  → delayed by 103ms 1ms  → delayed by 102ms 100ms → delayed by 3ms 300ms → delayed by 2ms 600ms → delayed by 1ms ``` → 0ms and 1ms were ready instantly, but blocked by the loop → 100ms fired right as the stack cleared → 300ms and 600ms had almost zero extra delay (That ~1-2ms you see even on 300ms/600ms? That's just Event Loop & system overhead — unavoidable.) I've known how the Event Loop works for years. But seeing the actual pattern in milliseconds — that was oddly satisfying. There's a difference between knowing something and feeling it click at a deeper level. #JavaScript #EventLoop #AsyncProgramming

Deep Dive into Node.js Architecture A simple architecture diagram can look complicated at first. Event Loop. Thread Pool. libuv. Callbacks. But once I broke it down step by step, the flow became much clearer. Node.js is often described as single-threaded. What I learned is that this doesn’t limit its ability to handle concurrency — it just handles it differently. JavaScript executes inside the V8 engine on a single main thread. When an asynchronous operation is triggered — like a file read, API call, or database query — Node.js does not pause execution. Instead: • The task is delegated to libuv • libuv manages a thread pool for blocking I/O operations • Once completed, the callback is pushed into the Event Queue • The Event Loop continuously checks the call stack and executes callbacks when it becomes free The key insight for me was this: Node.js scales not because it creates more threads, but because it keeps the main thread free and coordinates asynchronous work efficiently. Understanding this internal flow changed the way I think about backend performance and system design. Next, I’ll dive deeper into how the Event Loop phases actually work. #NodeJS #BackendDevelopment #JavaScript #SystemDesign #LearningInPublic #MERNStack