SUSILAKASH RAJ A’s Post

Day 9 / 30 - Javascript Coding Problem: Given an integer array nums, a reducer function fn, and an initial value init, return the final result obtained by executing the fn function on each element of the array, sequentially, passing in the return value from the calculation on the preceding element. This result is achieved through the following operations: val = fn(init, nums[0]), val = fn(val, nums[1]), val = fn(val, nums[2]), ... until every element in the array has been processed. The ultimate value of val is then returned. If the length of the array is 0, the function should return init. Please solve it without using the built-in Array.reduce method. Solution: var reduce = function (nums, fn, init) { let numsLength = nums?.length; if (numsLength === 0) { return init; } let acc = init; for (let k = 0; k < numsLength; k++) { acc = fn(acc, nums[k]); } return acc; }; #JavaScript #DSA #CodingPractice #100DaysOfCode #FrontendDevelopment #ProblemSolving

Assalam o Alaikum everyone, JavaScript Lesson 30 is here: Pure Functions, Higher-Order Functions, Function Composition & Currying. This lesson focuses on functional programming concepts that help you write cleaner, more reusable, and more predictable JavaScript code. I started with pure functions and explained why they are important: same input, same output, and no side effects. Then I showed the difference between pure and impure functions using real examples like add() and an increment() function that changes external state. After that, I covered higher-order functions, where functions can accept other functions as arguments or return a function as output. I also demonstrated how to create reusable behavior with a function that returns another function, like createGreeter(). Next, I explained function composition using pipe(), which lets you chain transformations together in a clean left-to-right flow. Finally, I covered currying and partial application, showing how one function can be broken into smaller reusable steps. In this lesson, you will learn: • pure vs impure functions • side effects in JavaScript • higher-order functions • returning functions from functions • function composition with pipe() • currying and partial application • arrow function currying This is a very useful lesson for anyone who wants to understand functional programming patterns in JavaScript and write better code in real projects. Watch the lesson: https://lnkd.in/dVyfGvcP #JavaScript #PureFunctions #HigherOrderFunctions #Currying #FunctionComposition #FunctionalProgramming #JavaScriptTutorial #WebDevelopment #FrontendDevelopment #Programming #DeveloperMaroof #LearnJavaScript #JavaScriptConcepts #CleanCode #JavaScriptLessons

🚀 Day 4 of my JavaScript Coding Practice Today’s problem: Two Sum var twoSum = function(nums, target) { const map = new Map(); // Store: { value : index } for (let i = 0; i < nums.length; i++) { const complement = target - nums[i]; // If the needed number is already in our map, we found the pair! if (map.has(complement)) { return [map.get(complement), i]; } // Otherwise, save the current number and its index map.set(nums[i], i); } return []; // Return empty if no pair is found }; 💡 Instead of using brute force (O(n²)), I used a HashMap approach to solve it in O(n) time. Key takeaway: Understanding how to trade space for time can significantly optimize performance. Small steps every day → Big improvements over time 📈 #JavaScript #DSA #CodingPractice #100DaysOfCode #FrontendDevelopment

Assalam o Alaikum everyone, JavaScript Lesson 29 is here: Reference vs Value, Shallow Copy, Deep Copy & Immutable Patterns. This lesson covers one of the most important JavaScript concepts for writing clean and predictable code: understanding how values are stored, copied, and updated in memory. I explained the difference between primitive values and reference values, then demonstrated what happens when you assign objects and arrays directly. From there, I showed how to create shallow copies using spread syntax and Object.assign(), and why shallow copy can still cause problems with nested objects. I also covered deep copy using both: - JSON.parse(JSON.stringify()) - structuredClone() After that, I moved into immutable programming patterns, where I showed how to update arrays and objects without mutating the original data using: - filter() - map() - spread syntax - destructuring This is a very practical topic for JavaScript developers because immutability helps prevent bugs and makes code easier to maintain in real projects. Watch the lesson: https://lnkd.in/dSeTxYPP #JavaScript #ReferenceVsValue #ShallowCopy #DeepCopy #ImmutablePatterns #JavaScriptTutorial #WebDevelopment #FrontendDevelopment #Programming #CodingTutorial #DeveloperMaroof #LearnJavaScript #JavaScriptBasics #ModernJavaScript #SpreadOperator #ObjectAssign #StructuredClone #Immutability #JSConcepts #JavaScriptLessons

One small word in JavaScript causes a lot of confusion: undefined. Many developers encounter it but don’t fully understand why it appears. In my latest article, I break it down in a practical way: • What undefined actually means • Common scenarios where it shows up • Mistakes developers often make • How to avoid it in real projects This is especially useful if you're learning JavaScript or improving your debugging skills. 🔗 Read the full article: https://lnkd.in/gaGDuAHp Curious — what was the most confusing JavaScript concept for you when you started? #JavaScript #WebDevelopment #FrontendDevelopment #Programming #Coding #SoftwareDevelopment #Debugging #LearnJavaScript

🚀 Day 7 / 30 - JavaScript Coding Practice Today’s challenge: Recreating the Array.map() functionality — without actually using it 👀 Problem: Apply a transformation function to each element of an array and return a new array. 💡 Key Insight: This problem helped me understand what’s happening under the hood of built-in methods like map(). 👉 Instead of relying on .map(), I used a loop to: Iterate through each element Apply the given function with both value & index Build a new transformed array Solution: var map = function (arr, fn) {     let transArr = []     arr.forEach((element, i) => {         transArr.push(fn(element, i) ?? element);     });     return transArr; }; #JavaScript #DSA #CodingPractice #100DaysOfCode #FrontendDevelopment #ProblemSolving

🧠 JavaScript Myth Busting: "Let and Const are not Hoisted" (Yes, they are!) Have you ever been told in an interview that "let" and "const" aren’t hoisted, but "var" is? It’s one of the most common misconceptions in JavaScript. 👉 Here is the 100% technical truth: All declarations in JavaScript ("var", "let", "const", "function", "class") are hoisted. So, why do they behave differently? It’s all about Initialization and a friendly little neighborhood called the Temporal Dead Zone (TDZ). --- 🚨 The Difference: 1️⃣ "var" is hoisted AND initialized immediately with the value of "undefined". You can access it before its line of code without crashing. 2️⃣ "let" and "const" are hoisted BUT NOT initialized. The JavaScript engine knows they exist, but it reserves the memory without setting any starting value. --- 💀 Enter the Temporal Dead Zone (TDZ): The TDZ is the period of time between the start of a block and the moment the variable is actually initialized (the line where you wrote the declaration in your code). If you try to touch a "let" or "const" variable while it is trapped in the TDZ, JavaScript throws a ReferenceError. --- 💡 Why does this matter? The TDZ exists to enforce better coding practices. It helps prevent bugs by stopping you from using variables that have been created but aren't yet ready for use. --- 📌 Check out the image below for a simple breakdown! 👇 💬 Drop your best analogies in the comments! #javascript #coding #webdevelopment #programmingmyths #softwareengineering #learncoding #frontend

Day 15 / 30 - Javascript Coding practice Problem : Longest Common Prefix Find the longest common prefix among an array of strings. If there’s no common prefix, return an empty string "". Solution: var longestCommonPrefix = function (strs) { let longestStr = strs[0] for (let k = 1; k < strs.length; k++) { let j = 0; while (j < strs[k].length && j < longestStr.length && strs[k][j] === longestStr[j]) { j++; } longestStr = longestStr.slice(0, j) if (longestStr === "") return "" } return longestStr; }; #JavaScript #DSA #CodingPractice #100DaysOfCode #ProblemSolving #FrontendDevelopment

Understanding the Event Loop in JavaScript is a turning point for every developer. Many developers use async features like promises, setTimeout, or async/await daily — but very few truly understand what happens behind the scenes. I’ve written a detailed yet easy-to-understand article that breaks down: ✔ Call Stack ✔ Callback Queue ✔ Microtask Queue ✔ Execution Order If you want to strengthen your JavaScript fundamentals and avoid common async mistakes, this will definitely help. 👉 Read the full article: https://lnkd.in/gDhwvmUc I’d love to hear your thoughts — what was the hardest concept for you when learning the Event Loop? #JavaScript #SoftwareDevelopment #WebDevelopment #FrontendDevelopment #AsyncProgramming #Coding #TechLearning

"If you’re not using "map", "filter", and "reduce" in JavaScript… you're probably writing more code than needed." 😅 These 3 array methods can level up your code instantly 👇 🔹 map() 👉 Transforms each element of an array 👉 Returns a new array 💻 Example: const nums = [1, 2, 3]; const doubled = nums.map(n => n * 2); // [2, 4, 6] 🔹 filter() 👉 Filters elements based on a condition 👉 Returns a new array 💻 Example: const nums = [1, 2, 3, 4]; const even = nums.filter(n => n % 2 === 0); // [2, 4] 🔹 reduce() 👉 Reduces array to a single value 👉 Very powerful (but often misunderstood) 💻 Example: const nums = [1, 2, 3, 4]; const sum = nums.reduce((acc, curr) => acc + curr, 0); // 10 🚀 Pro Tip: Use "map" for transformation, "filter" for selection, and "reduce" for everything else. 💬 Which one do you use the most in your projects? #javascript #webdevelopment #mern #coding #developers