JavaScript Expression Evaluation Fundamentals

You know how JavaScript performs one function at a time and it becomes time consuming when a function takes too long to complete? This is because Js is a single threaded language and this behavior is called as synchronous. It can perform one task at a time which blocks other code. This can be solved by using Asynchronous functions (non-blocking way). JavaScript can execute code in two different ways: Synchronous (Blocking) Code runs line by line Each task waits for the previous one to finish If one task is slow, everything else pauses Think of it as a single-lane road. Asynchronous (Non-blocking) Time-consuming tasks run in the background JavaScript continues executing other code Once the task is done, the result is handled. In the next post I will tell how asnyc functions work. See you later. Cheers!! #JavaScript #WebDevelopment #MERN #AsyncJS #LearningInPublic

🔥 Event Loop trap: If you miss this output, async JS will bite you in production 😅 ❓What’s the output order? A) A E G C D F B B) A G E C D F B C) A E G B C D F D) A E C D F G B 💬 Drop your answers + reasoning 👇 #CodeSnatch #javascript #eventloop #asyncawait #interviewprep #webdevelopment

JAVASCRIPT NOTES — PART 5 Some JavaScript bugs aren’t about logic — they’re about understanding how the language behaves internally. This post covers: • Stack vs Heap (how memory is handled) • Shallow vs Deep copy • The real behavior of the `this` keyword • Garbage collection basics • Debouncing & Throttling for UI performance These are the concepts that explain why code behaves the way it does. Once memory and execution flow are clear, JavaScript becomes far more predictable. #JavaScript #WebDevelopment #FrontendDeveloper #InterviewPrep #LearningInPublic #Debouncing #Prototypes #Consistency

💡 Everything in JavaScript is an object (almost). ❓ Why is null also an object? When you check the type of null in JavaScript, you’ll see something strange: typeof null; // "object" 😵 But here’s the truth 👉 null is NOT actually an object. 🔹 So why does this happen? This is a historical bug from the early days of JavaScript. Internally, JavaScript used type tags to identify values, and null was given the same tag as objects. Once JavaScript became widely used, this mistake couldn’t be fixed—changing it would break millions of existing programs. 🔹 What is null really? null is a primitive value that means: “No value” “Intentionally empty” “Nothing here” It’s often used to reset variables or show that something is missing on purpose. ⚠️ Why this matters If you rely only on typeof, you can write buggy logic. if (typeof value === "object") { // This will also run for null ❌ } ✅ Best practice Always check for null explicitly: value === null; 💡 Takeaway null showing up as "object" is a JavaScript bug that became a feature. Knowing this helps you avoid confusing bugs and write safer code #learnwithisnaan #JavaScriptTips #ModernJavaScript #ES6 #DeveloperTips #CleanCode #JSDevelopers

Why try/catch Doesn’t Catch Everything in Async JavaScript try/catch works perfectly for synchronous errors. But in asynchronous JavaScript, it only works if you await the promise inside the try block. This is where many developers get confused. try/catch does not magically catch all async errors. It only catches: -Synchronous exceptions -Rejected promises that are properly awaited If a promise rejects outside of that boundary, the error escapes.

JAVASCRIPT NOTES — PART 3 (Async JavaScript) Synchronous code is easy to follow. Asynchronous code is where real confusion begins. This post covers: • Callbacks and why they became messy • Promises and their states • async / await for cleaner flow • Error handling with try–catch • The Event Loop and execution order • Microtasks vs callback queue Understanding async JavaScript isn’t about memorizing syntax — it’s about knowing when and why code executes. If the event loop ever felt confusing, this one is for revision. #JavaScript #WebDevelopment #FrontendDeveloper #LearningInPublic #InterviewPrep #AsyncJavaScript #Consistency

Ever clicked a button and noticed that the parent element’s event also runs? That happens because of event bubbling in JavaScript. When an event occurs, it travels up the DOM tree: Button → Parent → Document Sometimes this behavior causes unexpected results in your application. That’s where stopPropagation() helps. It stops the event from moving to parent elements. Example: element.addEventListener("click", (e) => { e.stopPropagation(); }); Now the event will stay on the current element only. Quick reminder: preventDefault() → stops browser default action stopPropagation() → stops event bubbling Understanding small concepts like this helps you write cleaner and more predictable JavaScript code. Follow for more JavaScript concepts explained visually. #javascript #webdevelopment #frontenddeveloper #coding #softwareengineering

Most developers say they “know” asynchronous JavaScript. They have: 1️⃣ Used async/await 2️⃣ Written API calls 3️⃣ Handled loading states But knowing syntax is different from understanding behavior. When the interviewer writes a small snippet on the board and asks: “What will be the output?” That’s where clarity is tested. Because async JavaScript is not about memorizing keywords. It is about: 1️⃣ Understanding execution order 2️⃣ Knowing how promise flow works 3️⃣ Reasoning about failure behavior

🚨 JavaScript Truth Bomb: “Everything is an object”… so why does typeof fn say "function"? Quick reality check: functions are objects in JS. But typeof goes a step further. It checks if that object is callable. If yes, it returns "function" instead of "object". That’s not a bug, it’s intentional: 🔥 Early JS needed a simple way to detect callable values 🔥 So functions got a special typeof result 🔥 They still behave like objects with extra behavior 👉 Functions are objects with a [[Call]] method capability. What weird JavaScript behavior confused you the most? 👇 #JavaScript #Coding #DeveloperLife #WebDev

🚀 JavaScript Errors — Now with cause How many times have you caught an error, wrapped it in a higher-level message, and completely lost the original context? That’s exactly the problem the new Error(..., { cause }) option solves. Instead of overwriting, you can now chain errors and preserve the root cause. The difference in DevTools is huge: Without cause: you only see the high-level error. With cause: you see both the high-level error and the original error that triggered it. This makes debugging much easier, especially in layered systems where abstraction often hides the real failure. 💡 My takeaway: start using cause when re-throwing errors. It’s a small feature with a big impact on developer experience. hashtag #javascript #webDevelopment #codingTip