JavaScript map() function returns undefined

Today I finally sat down to figure out the difference between Normal Functions and Arrow Functions in JavaScript. 😅 If you're like me and thought it was just about saving a few keystrokes, here is what I learned: 🛑 Normal Functions (function) Flexible this: The value of this changes depending on how you call the function. Constructors: You can use them with new to create objects. Hoisting: You can call them before they are even defined in your code. ⚡ Arrow Functions (=>) Predictable this: They "inherit" this from the code around them. No more .bind(this) hacks! Clean Code: Great for one-liners and array methods like .map() or .filter(). No arguments: They don't have their own arguments object (use ...rest instead). My takeaway: Use Normal functions for object methods and Arrow functions for almost everything else (especially callbacks). #JavaScript #LearningToCode #WebDev #CodeNewbie #Programming

JavaScript Prototype Explained Simply (Must Know Concept) Why Prototype Matters? ✔ Code Reusability ✔ Memory Efficient ✔ Enables Inheritance ✔ Foundation of JavaScript Classes Array.prototype → Object.prototype → null Methods like: • push() • pop() • map() • filter() Come from Array.prototype const arr = [10, 20, 30]; console.log(arr.__proto__ ===Array.prototype); // true If you're learning JavaScript, mastering Prototype is a game changer 💪 #JavaScript #WebDevelopment #Frontend #Programming #Developers #CodingJourney

Mastering JavaScript Closures: A Comprehensive Guide with Practical Examples JavaScript closures are a fundamental concept that allows a function to remember and access its lexical scope even when it's executed outside that scope. This tutorial demystifies closures, explaining their mechanics, practical applications, and how they empower powerful design patterns in your JavaScript code. Read the full article 👇 https://lnkd.in/gK4b6gvw #Technology #Programming #WebDevelopment #SoftwareEngineering #Coding #JavaScript #JSClosures #JavaScriptClosures #FunctionalProgramming #FrontendDevelopment #FutureOfWork #DigitalTransformation

🐞 A tiny JavaScript mistake that can break your code. Look at this snippet: function check(){ let first = 1; let First = 1; let res = 0; if(first == First){ res = 1; return res; } } console.log(res); Looks simple, right? But running this code will throw a ReferenceError. Here’s why 👇 🔹 JavaScript is case-sensitive first and First are two different variables. 🔹 Function scope matters res is declared inside the function, so it cannot be accessed outside of it. That’s why this line fails: console.log(res); ✅ Correct way: const result = check(); console.log(result); 💡 Lesson: Most bugs in programming aren't complex algorithms — they’re small details like scope, naming, and function usage. And those details matter. What’s the smallest bug that cost you the most debugging time? 👨💻 #JavaScript #CodingTips #WebDevelopment #Programming #DeveloperLife

🚀 60 Days JavaScript Challenge | Day 4 Today’s practice was about understanding loops and how repetition works in programming. ✅ Problem: Print numbers from 1 to 10 using JavaScript. 💡 Explanation: Instead of writing multiple console.log() statements manually, a for loop helps repeat the same action automatically. A loop has three parts: 1️⃣ Initialization – starting value 2️⃣ Condition – how long the loop should run 3️⃣ Increment – how the value changes each step The loop continues executing until the condition becomes false. 🎯 What I learned today: Loops are powerful because they reduce repetitive code and make programs efficient. Understanding loop flow is essential before moving to advanced problem solving. Consistency continues. Day 5 coming next ✅ #60DaysOfCode #JavaScript #CodingPractice #ProblemSolving #LearningJourney

Unpopular opinion: "Performance" is a feature, not an afterthought. Most devs wait until the site feels "heavy" to start optimizing. By then, your bounce rate has already spiked. I wanted to make the technical side of speed easier to digest, so I built a checklist with the exact benchmarks you should be hitting in 2026 Whether you're a junior dev or a senior architect, this should be in your bookmarks. 🔖 Link: https://lnkd.in/eq_Np6JJ #WebDesign #Programming #TechTips #JavaScript

Topic: DOM Manipulation in JavaScript | Dynamic Shape Generator In this video, you will learn: 1). How to select HTML elements using JavaScript 2). How to handle button click events 3). How to create and style shapes dynamically 4). How to display elements based on user input Outcome: Understand how JavaScript can dynamically update webpage content using DOM manipulation. Inspired by concepts from GeeksforGeeks. Vikas Kumar #JavaScript #WebDevelopment #Coding #DOM #FrontendDevelopment #LearnToCode #100DaysOfCode #Developers #Programming #GeeksforGeeks

Mastering JavaScript: Working with Arrays of Objects Using Reduce Just uploaded a comprehensive multi-page PDF guide on how to effectively handle arrays of objects in JavaScript using the reduce method! 🚀 Whether you're summing values, grouping data by properties, counting occurrences, or merging nested arrays, this guide breaks down these essential patterns with clear examples and practical problems. If you want to write cleaner and more efficient code when working with complex data structures, this is for you! Feel free to download the PDF, try out the examples, and share your questions or insights in the comments. Let’s level up our JavaScript skills together! 💻✨ #JavaScript #CodingTips #WebDevelopment #Programming #CodeNewbie #Developer #LearnToCode #TechGuide #FrontEnd #ReduceMethod

Here’s something interesting about JavaScript’s single-threaded nature. If you run a long synchronous task (like a 10-second while loop), the UI freezes. During that time, if you click a button multiple times, nothing appears to happen. But when the loop finishes, all the clicks suddenly fire. Why? Because JavaScript is blocked — but your Operating System isn’t. Here’s what actually happens: Your mouse click sends a hardware interrupt to the OS. The OS records it in its input buffer. The browser receives the event and places it into the Macrotask Queue. The Event Loop cannot process the queue until the Call Stack is empty. When the synchronous task completes, the Event Loop finally runs again and processes all queued click events. JavaScript is single-threaded. The system underneath it is not. Understanding this explains many “weird” UI behaviors. #JavaScript #WebDevelopment #EventLoop #Programming

JavaScript doesn’t execute code randomly. Every time it runs, it creates an Execution Context ⚡ Understanding this concept makes hoisting and closures much easier to master. 🔹 Two Main Phases: 1️⃣ Memory Creation Phase • Variables are stored as undefined • Functions are stored completely in memory 2️⃣ Code Execution Phase • Code runs line by line • Values get assigned 🔹 Example: var a = 10; function greet() { console.log("Hello"); } 👉 Memory Phase: a → undefined greet → full function 👉 Execution Phase: a → 10 Once you understand Execution Context, debugging becomes much easier and JavaScript starts making logical sense instead of feeling “magical”. Connect with me on LinkedIn: https://lnkd.in/dx7fPEsy #JavaScript #ExecutionContext #FrontendDeveloper #WebDevelopment #Programming #Coding #Developers #TechContent #LearningInPublic 🚀