How does the JS event loop work?

Most devs learn JavaScript syntax, not behavior. That’s why we see weird bugs that make no sense; until you understand what’s actually happening under the hood. Here are 5 common mistakes (and how to fix them): 1️⃣ Hoisting confusion Variables declared with var are hoisted, but their values aren’t. ✅ Use let or const; they’re block-scoped and predictable. 2️⃣ Loose equality traps == converts types before comparing, leading to chaos. Always use === to avoid surprise conversions. 3️⃣ Misunderstanding closures Closures let functions “remember” the scope where they were created. They’re powerful for managing state and data privacy. 4️⃣ Ignoring the event loop JS runs on a single thread — async code doesn’t mean “parallel.” Understanding how the event loop works will help you debug async issues faster. 5️⃣ Misusing this Arrow functions inherit this from their parent. Regular functions bind it dynamically. Know the difference, or you’ll end up debugging ghosts. 👻 #JavaScript #WebDevelopment #FrontendDevelopment #CodingTips #Programming #SoftwareEngineering #Developer #LearningToCode #DevCommunity

🚀 Day 8 of My 30 Days of JavaScript Journey ✅ Challenge: Function Composition (LeetCode #2629) Build a function compose(functions) that returns a new function representing the composition of all given functions. When called with an input x, it evaluates from right to left, applying each function in sequence. If no functions are provided, it returns the identity function — meaning f(x) = x. 💻 Language Used: JavaScript ❓ Problem Link: https://lnkd.in/gEXnFK4d 💡 Solution: https://lnkd.in/gjKcFQvB 🧠 Concept Highlighted: This challenge explores function composition, a key concept in functional programming, showing how multiple simple functions can combine to form powerful transformations. It reinforces the importance of execution order and function chaining in JavaScript. #Day8 #JavaScript #LeetCode #30DaysOfCode #CodingChallenge #WebDevelopment #FrontendDevelopment #FunctionalProgramming #LearningEveryday #ProblemSolving

Let’s decode three of the most confusing JavaScript topics 👇 🔹 1. Scope Scope defines where your variables and functions are accessible. Global Scope: Accessible everywhere in the code. Function Scope: Accessible only inside a function. Block Scope: (introduced with let & const) accessible only within { }. 🔹 2. Hoisting JavaScript moves declarations to the top of their scope before code execution. But remember — only declarations are hoisted, not initializations. That’s why var behaves differently than let and const. 🔹 3. TDZ (Temporal Dead Zone) The period between entering a scope and initializing a variable declared with let or const. Accessing a variable in TDZ results in a ReferenceError — it exists but isn’t accessible yet! #JavaScript #FrontendDevelopment #WebDevelopment #Coding #Programming #LearnToCode #Scope #Hoisting #TDZ

🚀 Day 1 of How JavaScript Really Runs! Ever wondered what happens behind the scenes when you run your JavaScript code? 🤔 Here’s a quick breakdown of the magic inside the V8 engine 👇 1️⃣ Your JavaScript code — the human-readable code you write. 2️⃣ Parsing — the engine parses it into an Abstract Syntax Tree (AST) 🌲, which represents the structure of your code. 3️⃣ Interpreter (Ignition) — converts the AST into bytecode and starts executing it quickly. 4️⃣ Optimizing Compiler (TurboFan) — watches the execution and compiles frequently used parts into highly optimized machine code ⚡ 💡 This combination of interpreting and compiling helps JavaScript achieve both speed and efficiency, making it one of the most powerful languages for web development today. #JavaScript #V8Engine #WebDevelopment #Programming #DeveloperCommunity #LearningEveryday Sudheer Velpula

Day 7 of #30DaysOfJavaScript: Solved the Function Composition Challenge! 🎉 Today's problem involved creating a function that composes an array of functions and applies them from right to left, just like mathematical function composition 𝑓(𝑔(ℎ(𝑥))) f(g(h(x))). Using JavaScript's reduceRight, I built a clean, efficient solution that handles composing any number of functions—even when the array is empty (returning the identity function). This challenge sharpened my understanding of higher-order functions and functional programming concepts. Here’s a quick look at the core idea: js const compose = (functions) => (x) => functions.reduceRight((acc, fn) => fn(acc), x); Example: Input functions: [x => x + 1, x => x * x, x => 2 * x] Input value: 4 Output: 65 Excited to keep growing and sharing every step in this coding journey! #JavaScript #LeetCode #FunctionalProgramming #CodeChallenge #WebDevelopment #LearningJourney #Programming

JavaScript Closures Explained 💡 A closure is a powerful feature in JavaScript where an inner function retains access to variables from its outer function, even after the outer function has finished executing. This means the inner function "remembers" the environment it was created in. Closures enable data encapsulation, function factories, and help with keeping state in asynchronous code. Example: function outer() { let count = 0; return function inner() { count++; console.log(count); }; } const counter = outer(); counter(); // 1 counter(); // 2 counter(); // 3 Here, inner remembers the count variable even after outer is executed. This is what makes closures so useful! #JavaScript #Closure #WebDevelopment #JavaScriptClosures #Coding #Programming #LearnJavaScript #FrontendDevelopment #DevTips #JavaScriptTips #CodeNewbie

🚀 Efficient Task Scheduling with JavaScript (LeetCode 621: Task Scheduler) Today I explored an interesting problem — scheduling tasks with cooldown periods efficiently. 🔹 Problem: Given a list of tasks (like ['A', 'A', 'A', 'B', 'B', 'B']) and a cooldown interval n, find the least number of intervals needed to finish all tasks without breaking the cooldown rule. 🔹 Key Idea: Count the frequency of each task. Sort to find the most frequent task. Use idle slots to manage cooldowns. Minimize idle time and calculate total intervals. 💡 Learning: This problem taught me how to use frequency counting, sorting, and greedy scheduling together to reduce idle time and improve performance. #JavaScript #TypeScript #Coding #ProblemSolving #LeetCode #WebDevelopment #TechLearning

💡 Understanding Object Methods in JavaScript Working with objects is fundamental in JS. Here's a quick overview of some powerful methods: Object.keys(obj) → Returns all keys of the object. Object.values(obj) → Returns all values of the object. Object.entries(obj) → Returns key-value pairs as arrays. obj.hasOwnProperty("property") → Checks if the object has a specific property. Object.assign({}, obj, { newProperty: "newValue" }) → Creates a new object by merging existing ones. 👉 View the full example on GitHub: https://lnkd.in/dDN-vDkD #JavaScript #FullStack #100xDevs #WebDevelopment #Coding #JSConcepts #LearnJavaScript

🚀 Day 6 of My 30 Days of JavaScript Challenge 🧩 Problem: Filter Elements from Array (LeetCode #2634) Given an integer array arr and a filtering function fn, return a new array filteredArr that only includes elements where fn(arr[i], i) returns a truthy value. Solve this without using the built-in Array.filter() method. 💻 Language: JavaScript ❓ Question: https://lnkd.in/eSGpgXcM 💡 Solution: https://lnkd.in/ekA6y-u3 🧠 Concepts Used: Higher-order functions and callbacks Conditional checks for truthy/falsy values Understanding Boolean(value) behavior in JavaScript 📚 Takeaway: Rebuilding filter() from scratch deepens understanding of conditional logic, iteration, and truthy/falsy evaluation — all essential for functional programming in JavaScript. #Day6 #JavaScript #30DaysOfCode #LeetCode #CodingChallenge #WebDevelopment #FrontendDevelopment #100DaysOfCode