Quick Object Inspection with NodeJS

I had a function using Array.map(). The output was always undefined. At first I assumed: “map automatically returns transformed values.” ❌ Wrong assumption. Root cause: I forgot to return a value inside the callback. map does NOT mutate or guess logic. No return = undefined. Fix: Explicitly return the value. Small mistake, big logic lesson: JavaScript array methods are declarative, not magical. // ❌ Bug const nums = [1, 2, 3]; const result = nums.map(n => {  n * 2; }); // ✅ Fix const fixed = nums.map(n => {  return n * 2; }); #JavaScript #FrontendDevelopment #ProgrammingBasics #CleanCode #WebDevelopment

JavaScript Notes to Escape Tutorial Hell (12/20) Most developers know that closures "remember" variables But few can explain the cost. Does a closure keep everything from its parent in memory? Or just what it needs? This deck explains: - How closures enable data privacy and encapsulation - How nested scopes and parameters interact - How global and local variables behave inside closures - What happens to closure variables in memory - How the garbage collector decides what to keep - Using closures with constructor functions - Building reusable logic like private counters (increment / decrement) #JavaScript #WebDevelopment #Closures #GarbageCollection #CodingJourney #SoftwareEngineering #InterviewPrep #FrontendDeveloper

console.log() is the most powerful debugging tool you have. Forget fancy debuggers. When your code breaks, just log everything: console.log('Function started') console.log('User data:', userData) console.log('Before API call') console.log('API response:', response) console.log('After processing') This shows you: → Where your code is actually breaking → What your variables actually contain → If your function is even running Most bugs happen because you THINK the code is doing one thing. But it's actually doing something else.console.log() shows you the truth. Every senior developer still uses it daily. It's not amateur. It's effective. When stuck, don't stare at your code for 2 hours. Add 10 console. logs and run it again. The answer will show itself. #debug #log #developer #react #javascript #nodejs #tech

JavaScript Notes to Escape Tutorial Hell (19/20) If you are still writing for loops to transform arrays, you are writing more code than you need to. In modern JavaScript, most array problems don’t need loops. They need the right higher-order functions. This deck explains: - How map transforms data - How filter selects data - How reduce aggregates data into a single value - How to use real-world data (API-style objects) - How chaining leads to cleaner, readable code - Why functional patterns are preferred over traditional loops If you master these three, array manipulation becomes effortless. #JavaScript #WebDevelopment #FunctionalProgramming #MapFilterReduce #CleanCode #CodingJourney #SoftwareEngineering #InterviewPrep #FrontendDeveloper

 Why delete Works Here… But Not There This morning’s code was: let x = 10; const obj = { x: 20 }; delete x; delete obj.x; console.log(x); console.log(obj.x); 💡 Correct Output 10 undefined 🧠 Simple Explanation : 🔹 Line 1: delete x; Here’s the important rule 👇 👉 delete cannot remove variables declared with let, const, or var. So this line: delete x; does nothing. x still exists with value 10. ✔ Output: 10 🔹 Line 2: delete obj.x; Now this is different 👀 obj.x is a property of an object delete can remove object properties So after: delete obj.x; The property x no longer exists on obj. Accessing it returns: undefined ✔ Output: undefined 🎯 Key Takeaways : delete ❌ does NOT work on variables delete ✅ works on object properties Removing a property ≠ setting it to undefined let / const variables are protected from deletion 📌 That’s why delete is mostly used with objects, not variables. 💬 Your Turn Did you expect both deletes to work? 😄 Comment “Surprised 😮” or “Knew this 👍” #JavaScript #LearnJS #FrontendDevelopment #CodingInterview #Objects #TechWithVeera #WebDevelopment

ON wasn’t built for real JavaScript data. This talk introduces JSBT, a new binary format made for JS object graphs—supporting circular refs, Maps, Sets, BigInt, classes, and more. See how 10,000 objects shrink to 62KB and why it changes JS services a talk by Alexander Cheprasov https://lnkd.in/d_bKgwWW #CityJSLondon #JavaScript #Perfomance #DataSerialization

A real-world example of how the language chosen can have a dramatic effect on results: Get All Tasks from a ClickUp Workspace #Javascript: using async/await promise.all to send batched requests with a 10 second wait I was able to fetch 69,726 tasks in 268.69 seconds. #Go: using bucket rate limiting to send a request every 60 milliseconds in Go routines channeling data to a separate Go routine processing the output I was able to fetch 69,726 tasks in just 44.543 seconds.

Day 5 | Data Structures & Algorithms with JavaScript Practiced merging two arrays using core JavaScript logic, without relying on built-in methods. This exercise helped me strengthen my understanding of: • Looping and indexing • Array manipulation fundamentals • Writing clean, logical code • Verifying output through browser console Focusing on building strong fundamentals step by step to improve problem-solving skills. 📌 Topic: Merge Two Arrays 📌 Tech: JavaScript #DSA #JavaScript #ProblemSolving #SoftwareDevelopment #FrontendDevelopment #LearningJourney #Consistency #LinkedInLearning

💡 RTK Query Tip: skipToken vs skip — Know the Difference When conditionally fetching data in RTK Query, choosing between skip and skipToken really matters. 👉 skipToken • No query is created • No cache key • No argument validation • Fully type-safe 👉 skip • Hook still runs • Cache entry may exist • Requires valid arguments • Fetch is simply paused 📌 Rule of thumb: If your query depends on a value that may be undefined (IDs, params, tokens), skipToken is the safer and cleaner choice. Small decisions like this lead to cleaner code, fewer bugs, and better performance 🚀 #React #ReduxToolkit #RTKQuery #JavaScript #TypeScript #WebDevelopment #Frontend #CleanCode #DevTips

Day 178: Beyond the Array 🔗 Today, I moved away from the comfort of Arrays and tackled a fundamental building block of Data Structures: Linked Lists. While Arrays are great for quick access, Linked Lists taught me the power of manual memory management and pointer manipulation. I spent the day implementing LeetCode 707 (Design Linked List) from scratch in JavaScript. Key takeaways from today’s build: ✅ Dynamic Growth: Unlike arrays, I don’t need to "shift" elements to add to the front. It’s a simple $O(1)$ re-wiring of pointers. ✅ The Traverse: To find a value, you have to walk the chain. $O(n)$ search is the trade-off for flexible insertion. ✅ Garbage Collection: Deleting isn’t about erasing data; it’s about "unlinking" it so the system can reclaim that space. Mastering the logic of node.next and head is a rite of passage. It’s making me a more conscious programmer—thinking about how data is actually structured in memory rather than just how it looks on the screen. Next up: Reversing the list and tackling Doubly Linked Lists! 🚀 #100DaysOfCode #JavaScript #DSA #LinkedList #LeetCode #SoftwareEngineering #ProblemSolving #CodingJourney #BuildInPublic