Build a mini Typed API Wrapper using native fetch. The goal was to ensure that all data coming from a public API was strictly typed before it reached the frontend. Core concepts I learned: Passing Generic Functions: I built a 'handleData<T>' function that takes the URL and the generic fetcher function as arguments '(datafetcher: (url: string) => Promise<T[]>)'. This keeps the data-handling logic highly modular. Generic Scoping: I learned the difference between an outer generic and an inner generic. By declaring <T> on the outer wrapper function '(handleData<T>)', it locks the type in immediately. This forces any inner callback functions to strictly adopt that type, making the logic highly predictable. Parameter Contracts: I learned why we strictly type function arguments like 'datafetcher: () => Promise<T[]>'. It acts as a strict contract (or a bouncer). It does not tell the fetcher what to do; instead, it protects the main function from accidentally accepting a callback that returns the wrong kind of data. The Async/Await Illusion: A major realization was that await does not make code synchronous. It simply pauses that specific function and yields control back to the main thread so the browser UI does not freeze. Because the function pauses, the async keyword automatically and synchronously returns a Promise (an IOU) to keep the rest of the application running smoothly. #TypeScript #AsyncProgramming #JavaScript #WebDev #LearningInPublic #StudentDeveloper #APIs
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🚀 Mastering Async/Await in JavaScript (Without the Headaches) If you’ve ever dealt with messy ".then()" chains in JavaScript, you know how quickly things can get out of hand. That’s where async/await comes in — making asynchronous code look and behave more like synchronous code. 🔹 What is async/await? It’s a modern way to handle asynchronous operations in JavaScript, built on top of Promises. 🔹 Basic Example: async function fetchData() { try { const response = await fetch('https://lnkd.in/gDCe34XD'); const data = await response.json(); console.log(data); } catch (error) { console.error('Error:', error); } } 🔹 Why use async/await? ✔ Cleaner and more readable code ✔ Easier error handling with "try...catch" ✔ Avoids “callback hell” and long ".then()" chains 🔹 Key Points to Remember: - "async" makes a function return a Promise - "await" pauses execution until the Promise resolves - Use "try...catch" for error handling - Works only inside "async" functions 💡 Pro Tip: Use async/await for API calls, database queries, or any operation that takes time — your future self (and your teammates) will thank you. #JavaScript #WebDevelopment #AsyncAwait #CodingTips #Frontend #Developers
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⚡ Mastering Async/Await in Node.js – Write Cleaner, Smarter CodeTired of callback hell? 😵 Nested .then() chains confusing your logic?👉 Async/Await is the game-changer you need.🧠 What is Async/Await? It’s a modern way to handle asynchronous operations in JavaScript, built on top of Promises.async → makes a function return a Promiseawait → pauses execution until the Promise resolves🔧 Before (Promises):getUser() .then(user => getOrders(user.id)) .then(orders => console.log(orders)) .catch(err => console.error(err));✨ After (Async/Await):async function fetchOrders() { try { const user = await getUser(); const orders = await getOrders(user.id); console.log(orders); } catch (err) { console.error(err); } }💡 Why Developers Love It:Cleaner & more readable code 🧹Easier error handling with try/catchLooks like synchronous code, but runs async ⚡Reduces bugs in complex workflows🚀 Pro Tips:Use Promise.all() for parallel executionAvoid blocking loops with await inside for (use wisely)Always handle errors ❗🔥 Real-World Use Cases:API calls 🌐Database queries 🗄️File handling 📂Background jobs ⏳💬 One Line Summary: Async/Await turns messy async code into clean, readable logic.#NodeJS #JavaScript #AsyncAwait #CleanCode #WebDevelopment #BackendDevelopment
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𝟵𝟵% 𝗼𝗳 𝗝𝗦 𝗱𝗲𝘃𝗲𝗹𝗼𝗽𝗲𝗿𝘀 𝘄𝗿𝗶𝘁𝗲 𝗮𝘀𝘆𝗻𝗰 𝗰𝗼𝗱𝗲 𝗱𝗮𝗶𝗹𝘆. 𝗕𝘂𝘁 𝗺𝗼𝘀𝘁 𝗰𝗮𝗻'𝘁 𝗲𝘅𝗽𝗹𝗮𝗶𝗻 𝘄𝗵𝘆 𝗶𝘁 𝗮𝗰𝘁𝘂𝗮𝗹𝗹𝘆 𝘄𝗼𝗿𝗸𝘀. 👇 I didn't either until I learned about the JavaScript Runtime Environment. Here's the mental model that changed everything for me: JavaScript by itself is just a language. Runtime = Engine + APIs + Event Loop 🔥 What's actually running under the hood: ⚙️ JS Engine (V8) → converts code to machine code 📞 Call Stack → runs functions one by one 🌐 Web APIs → setTimeout, DOM, fetch (NOT part of JS itself!) 📬 Callback Queue → stores async callbacks ⚡ Microtask Queue → Promises, higher priority 🔄 Event Loop → the brain connecting everything The flow: Code → Call Stack → Web APIs → Queue → Event Loop → Call Stack Right now, try this 👇 console.log("Start"); setTimeout(() => console.log("Async"), 0); console.log("End"); Output → Start, End, Async 🤯 Even with 0 ms delay, "Async" prints LAST. That's the Event Loop doing its job. 🧠 Interview tip: Q: Why can JS handle async if it's single-threaded? A: The Runtime provides Web APIs + Event Loop + Queues — not the language. If this helped, repost ♻️ to help another developer. Follow Amit Prasad for daily updates on JavaScript and DSA 🔔 💬 Comment: Did you know that setTimeout 0ms still runs last? #JavaScript #WebDevelopment #Frontend #NodeJS #100DaysOfCode #DSA #Developer #CodingLife #TechLearning
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𝗦𝘆𝗻𝗰𝗵𝗿𝗼𝗻𝗼𝘂𝘀 𝘃𝘀 𝗔𝘀𝘆𝗻𝗰𝗵𝗿𝗼𝗻𝗼𝘂𝘀 𝗝𝗮𝘃𝗮𝗦𝗰𝗿𝗶𝗽𝘁 You need to understand how JavaScript runs code. It uses two ways: synchronous and asynchronous. Synchronous code runs line by line. Each line waits for the previous one to finish. If one task takes too long, your page freezes. Users are unable to click buttons. This is blocking code. Asynchronous code starts a task and moves to the next line. It does not wait. When the task finishes, JavaScript handles the result. This keeps your app smooth. setTimeout is a common example. It sets a timer and lets the rest of the code run. The timer finishes later. Fetch works the same way for API data. JavaScript uses these parts to manage tasks: - Call Stack: Runs sync code. - Web APIs: Handles long tasks like timers. - Callback Queue: Holds finished tasks. - Event Loop: Moves tasks from the queue to the stack when the stack is empty. Synchronous: - Runs in order. - Blocks the thread. - Simple but risks freezing the UI. Asynchronous: - Starts tasks and moves on. - Non-blocking. - Essential for network calls. JavaScript is single-threaded. Async behavior stops the screen from freezing. Source: https://lnkd.in/gZVb7V9R
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Day 5 ⚡ Async/Await in JavaScript — The Clean Way to Handle Async Code If you’ve struggled with .then() chains, async/await is your best friend 🚀 --- 🧠 What is async? 👉 Makes a function always return a Promise async function greet(){ return "Hello"; } greet().then(console.log); // Hello --- ⏳ What is await? 👉 Pauses execution until a Promise resolves function delay(){ return new Promise(res => setTimeout(() => res("Done"), 1000)); } async function run(){ const result = await delay(); console.log(result); } --- ⚡ Why use async/await? ✔ Cleaner than .then() chaining ✔ Looks like synchronous code ✔ Easier error handling --- ❌ Sequential vs ⚡ Parallel // ❌ Sequential (slow) const a = await fetchUser(); const b = await fetchPosts(); // ⚡ Parallel (fast) const [a, b] = await Promise.all([ fetchUser(), fetchPosts() ]); --- ⚠️ Error Handling try { const data = await fetchData(); } catch (err) { console.log("Error handled"); } --- 💡 One-line takeaway 👉 async/await = cleaner + readable way to handle Promises #JavaScript #AsyncAwait #WebDevelopment #Frontend #Coding #100DaysOfCode
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😵💫𝗢𝗻𝗲 𝗼𝗳 𝘁𝗵𝗲 𝗺𝗼𝘀𝘁 𝗰𝗼𝗻𝗳𝘂𝘀𝗶𝗻𝗴 𝘁𝗵𝗶𝗻𝗴𝘀 𝗶𝗻 𝗝𝗮𝘃𝗮𝗦𝗰𝗿𝗶𝗽𝘁: `...` At first glance, it looks simple. But depending on where you use it, it completely changes its role. Same syntax. Different behavior. That’s where most developers get tripped up. So I decided to break it down clearly: ✍️ New Blog Published: 𝗦𝗽𝗿𝗲𝗮𝗱 𝘃𝘀 𝗥𝗲𝘀𝘁 𝗢𝗽𝗲𝗿𝗮𝘁𝗼𝗿𝘀 𝗶𝗻 𝗝𝗮𝘃𝗮𝗦𝗰𝗿𝗶𝗽𝘁: 𝗘𝘅𝗽𝗮𝗻𝗱 𝗼𝗿 𝗖𝗼𝗹𝗹𝗲𝗰𝘁 𝗟𝗶𝗸𝗲 𝗮 𝗣𝗿𝗼 https://lnkd.in/gFPgrdEv 🔍 What you’ll learn: 🔹 When ... acts as a Spread Operator (expanding data) 🔹 When it becomes a Rest Operator (collecting data) 🔹 Real-world use cases to eliminate confusion Hitesh Choudhary Piyush Garg Chai Aur Code Anirudh J. Akash Kadlag Suraj Kumar Jha Nikhil Rathore Jay Kadlag DEV Community #JavaScript #WebDevelopment #TechnicalWriting #LearningInPublic #Chaicode #Cohort
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🚀 Async/Await in JavaScript — Write Asynchronous Code Like Synchronous! If Promises made async code cleaner, async/await made it beautiful. Let’s break it down 👇 🔹 What is async/await? • async makes a function return a Promise • await pauses execution until the Promise resolves 👉 It helps you write async code that looks and behaves like synchronous code. 🔹 Basic Example function fetchData() { return new Promise((resolve) => { setTimeout(() => resolve("Data received"), 2000); }); } async function getData() { const data = await fetchData(); console.log(data); } getData(); 🧠 Instead of chaining .then(), you write it step-by-step. 🔹 Error Handling Made Easy async function getData() { try { const data = await fetchData(); console.log(data); } catch (error) { console.error("Error:", error); } } ✅ No more messy .catch() chains ✅ Clean and readable error handling 🔹 Sequential vs Parallel Execution 👉 Sequential (waits one after another) await task1(); await task2(); 👉 Parallel (runs together) const [res1, res2] = await Promise.all([task1(), task2()]); ⚡ Use parallel execution for better performance when tasks are independent. 🔹 Common Mistakes to Avoid ❌ Using await outside async function ❌ Blocking loops with await unnecessarily ❌ Forgetting error handling 💡 Pro Tip: Async/await is just syntactic sugar over Promises — understanding Promises deeply makes async/await even more powerful. 🔥 Interview Question: What will be the output? async function test() { console.log("Start"); await Promise.resolve(); console.log("End"); } test(); console.log("Outside"); 👉 Comment your answer 👇 #JavaScript #AsyncAwait #WebDevelopment #Frontend #Coding #InterviewPrep
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🔑 Event loop functionality The Event Loop is a fundamental mechanism that allows JavaScript to perform non-blocking I/O operations, despite being a single-threaded language. It essentially acts as a traffic controller, managing how and when different pieces of code are executed. 🔑 Event Loop Explained: 1. Code runs on a single thread. ➡️ The code begins execution on a single thread (in JavaScript, that’s the main thread). 2. Functions go into the call stack. ➡️ Functions are executed one by one and placed on the call stack. ➡️ If a function finishes, it is removed from the stack. 3. Async tasks (like setTimeout) move to Web APIs. ➡️ When asynchronous operations (like setTimeout, fetch, or event listeners) are called, they are handed off to Web APIs or background systems. ➡️ These run independently and don’t block the main thread. 4. Completed tasks enter the callback queue. ➡️Once an async operation finishes, its callback is placed in the callback queue (also called the task queue). 5. Event loop checks if the stack is empty. The event loop constantly checks: ➡️Is the call stack empty? ➡️ Are there tasks waiting in the callback queue? 6. Executes callbacks in order. ➡️If the stack is empty, the event loop moves the first callback from the queue into the stack and executes it. ➡️This ensures tasks are processed in order without blocking. 7. Microtasks (Promises) run before callbacks. ➡️Promises and some other async tasks go into a microtask queue, which has higher priority than the callback queue. ➡️The event loop always clears the microtask queue before moving to the callback queue. 8. Cycle repeats endlessly. ➡️This cycle continues indefinitely, making the program responsive and able to handle multiple async operations smoothly.
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Every JavaScript developer has shipped this bug: async function processStream(response) { const reader = response.body.getReader() while (true) { const { done, value } = await reader.read() if (done) break processChunk(value) // ← throws an error } reader.releaseLock() // ← never reached. Stream locked forever. } The fix? A try...finally block you have to remember to write every single time. ES2026's using keyword makes this class of bug impossible. 🔒 using readerResource = { reader: response.body.getReader(), [Symbol.dispose]() { this.reader.releaseLock() } } // releaseLock() called automatically — even if processChunk throws Add [Symbol.dispose]() to any class, and using guarantees cleanup when scope exits — on return, on break, or on error. For async resources, await using + [Symbol.asyncDispose] handles it: await using redis = new RedisClient(config) // redis.quit() runs automatically when scope exits The proposal also ships: → DisposableStack — manage multiple resources, disposed LIFO → SuppressedError — preserves both errors if cleanup itself throws → Works in for loops — dispose at end of each iteration TypeScript has supported it since 5.2. Chrome 134+, Firefox 134+, Node.js 22+. Babel transpiles it for older targets. I wrote the complete guide for DB connections, transactions, streams, WebSockets, mutexes, perf timers, and DisposableStack patterns. Have you started using this yet? 👇 #JavaScript #ES2026 #WebDev #NodeJS #Programming #100DaysOfBlogging
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JavaScript Proxy — A Hidden Superpower You Should Know Most of us create objects like this: const frameworkName = { name: "Next JS" }; But what if you could intercept and control every operation on this object? That’s exactly what JavaScript Proxy does. Think of it like a gatekeeper sitting in front of your object — it can monitor, modify, or block any interaction. const frameworkName = { name: "Angular" }; const proxyFramework = new Proxy(frameworkName, { get(target, prop) { console.log(`Reading ${prop}`); return target[prop]; }, set(target, prop, value) { console.log(`Updating ${prop} to ${value}`); if (value === "React") { console.log("React is not allowed!"); throw new Error("React is not allowed!"); // Throw an error to prevent the update return false; // Prevent the update } target[prop] = value; return true; } }); proxyFramework.name; // 👉 Reading name proxyFramework.name = "Next"; Why should you care? ✔ Track changes (great for debugging) ✔ Add validation before updating values ✔ Build reactive behavior (like frameworks do) ✔ Control or restrict access to data Real-world use cases: • Form validation without extra libraries • Logging state changes for debugging • Building custom state management • Data sanitization before saving Pro Tip: Frameworks like Vue use Proxy internally to make data reactive. Understanding this can level up your frontend skills. Have you used Proxy in your projects, or are you still sticking with plain objects? #JavaScript #FrontendDevelopment #WebDevelopment #ReactJS #Coding #Programming #LearnToCode
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Repo (mono): https://github.com/asim-momin-7864/Typescript-learning/tree/main/practice-projects/9-Typed-API-Wrapper