Alexander Sakhatskii’s Post

Stop using Date in JavaScript for new projects The Date object is now officially legacy. TC39 is replacing it with the Temporal API. If you're still writing new Date() in 2026, you're shipping technical debt. Why Date is a problem: Mutable by default: Calling setDate changes the original object. That’s how you get surprise bugs in production. Months start at zero: January is 0. December is 11. Every dev has been burned by this at least once. Timezone chaos: new Date("2026-01-01") can give you Dec 31st at night depending on where your server runs. One object for everything: No way to represent just a date or just a time. It’s always a full datetime whether you want it or not. How Temporal fixes this: It’s immutable, so every operation returns a new value. Months start at 1 like normal humans expect. And you get specific types: PlainDate for dates only, PlainTime for time only, ZonedDateTime when you care about timezones, Duration for math. Instead of adding 86400000 milliseconds to add a day, you just write add one day. Way cleaner. What to do today: For new projects, use date-fns or Day.js until Temporal lands in browsers. If you want to be future-proof, try the @js-temporal/polyfill now. Temporal is Stage 3 and landing soon. Don’t let legacy APIs hold your codebase back. What are you using for dates in 2026? Let me know below 👇 #JavaScript #WebDev #Temporal #CleanCode #Frontend #TypeScript

🚀 JavaScript Output Prediction Challenge What will be the output? 🤔 💡 Important Behaviour: 👉 JavaScript executes code line by line 👉 The very first line throws the following: ❌ ReferenceError: a is not defined So in reality, the programme stops immediately and nothing else runs. 📌 Now, let’s understand what would happen inside the function (ignoring the first error): 👉 Before execution, JS does Hoisting (memory creation phase) Inside the function: var a → hoisted and initialized as undefined let b → hoisted but kept in Temporal Dead Zone (TDZ) (not accessible yet) 👉 Execution phase: "1:" → undefined (Because 'a' exists but not assigned yet) "2:" → ❌ ReferenceError (because b is in TDZ) After assignment: a = 10 b = 20 "3:" → 10 "4:" → 20 🔥 Core Concepts: JS has 2 phases → Memory Creation + execution. var → hoisted + usable as undefined let/const → hoisted but blocked by TDZ 💬 If you got this right, your JS fundamentals are solid 👇 #JavaScript #Hoisting #Frontend #CodingChallenge #WebDevelopment

𝑨𝒔𝒚𝒏𝒄𝒉𝒓𝒐𝒏𝒐𝒖𝒔 𝑱𝑺 (1) 🚀 𝑼𝒏𝒅𝒆𝒓𝒔𝒕𝒂𝒏𝒅𝒊𝒏𝒈 𝑪𝒂𝒍𝒍𝒃𝒂𝒄𝒌𝒔 𝒊𝒏 𝑱𝒂𝒗𝒂𝑺𝒄𝒓𝒊𝒑𝒕 (𝑻𝒉𝒆 𝑮𝒐𝒐𝒅 & 𝑻𝒉𝒆 𝑩𝒂𝒅) While diving deeper into asynchronous JavaScript, I explored one of the most fundamental concepts — Callbacks. 👉 𝑾𝒉𝒚 𝒄𝒂𝒍𝒍𝒃𝒂𝒄𝒌𝒔? JavaScript is synchronous by default, but callbacks help us perform operations asynchronously — like API calls, timers, or event handling. ✔️ 𝑮𝒐𝒐𝒅 𝑷𝒂𝒓𝒕: Callbacks allow us to: Handle async operations smoothly Execute code only after a task is completed Build real-world flows like order → payment → confirmation 🛒 𝑬𝒙𝒂𝒎𝒑𝒍𝒆: 𝘊𝘳𝘦𝘢𝘵𝘦 𝘰𝘳𝘥𝘦𝘳 → 𝘗𝘳𝘰𝘤𝘦𝘦𝘥 𝘵𝘰 𝘱𝘢𝘺𝘮𝘦𝘯𝘵 → 𝘚𝘩𝘰𝘸 𝘴𝘶𝘮𝘮𝘢𝘳𝘺 → 𝘜𝘱𝘥𝘢𝘵𝘦 𝘸𝘢𝘭𝘭𝘦𝘵 ❌ But here’s the catch… 👉 1. 𝑪𝒂𝒍𝒍𝒃𝒂𝒄𝒌 𝑯𝒆𝒍𝒍 (𝑷𝒚𝒓𝒂𝒎𝒊𝒅 𝒐𝒇 𝑫𝒐𝒐𝒎) When callbacks are nested inside each other, the code becomes: Hard to read Difficult to debug Painful to maintain 👉 2. 𝑰𝒏𝒗𝒆𝒓𝒔𝒊𝒐𝒏 𝒐𝒇 𝑪𝒐𝒏𝒕𝒓𝒐𝒍 We pass our logic into another function (like an API), and: We lose control over when/if it's executed We blindly trust external code This can lead to unexpected bugs 💡 𝐊𝐞𝐲 𝐋𝐞𝐚𝐫𝐧𝐢𝐧𝐠: Callbacks are powerful, but not scalable for complex flows. This is exactly why concepts like Promises and Async/Await were introduced. 🔥 Currently leveling up my async JS fundamentals step by step. Next stop → Promises! #JavaScript #AsyncJS #FrontendDevelopment #ReactJS #WebDevelopment #CodingJourney #Developers #LearningInPublic

Ever written JavaScript that *shouldn’t* work… but somehow does? 🤯 I remember staring at my screen thinking, “Did JS just ignore my logic?” Here’s the problem 👇 JavaScript has this hidden behavior called **hoisting**. It moves declarations (not values) to the top of the scope *before execution*. Sounds helpful… until it silently breaks your expectations. Here’s the insight 💡 * `var` gets hoisted and initialized as `undefined` * `let` & `const` are hoisted but stay in a “temporal dead zone” 🚫 * Functions? Fully hoisted — you can call them before defining! Example: ```js console.log(a); // undefined 😵 var a = 5; ``` Lesson learned 📌 JavaScript isn’t “weird” — it just follows rules we often ignore. Understanding hoisting = fewer bugs + cleaner logic. Now I always think: “What does JS see *before* running this?” 👀 If you’re diving deeper into JS concepts, I share more here 👉 https://webdevlab.org 🚀 Curious… have you ever been surprised by hoisting in your code? 😄 #JavaScript #WebDevelopment #Frontend #CodingTips #DevLife

A promise is just an object with two properties. The word "promise" sounds abstract. The actual thing is surprisingly concrete. When fetch() runs, JavaScript immediately returns an object - before any data has come back. That object has two properties: - value (undefined for now) - onFulfillment (an array of functions to run when value arrives) That's it. A placeholder with a slot for data and a list of what to do when it shows up. When the browser finishes the network request, it fills in value and auto-triggers everything in onFulfillment - passing the value as the argument. You get something immediately so your code can keep moving, and you attach behavior to a future value. That's the whole mechanism behind async JavaScript. Next: .then() - what it's actually doing (hint: not what the name implies). #JavaScript #WebDevelopment #SoftwareEngineering #Frontend

👉 Read here: https://lnkd.in/gq5rHZxB 🚀 Synchronous vs Asynchronous JavaScript Understanding how JavaScript executes code is key to writing efficient and non-blocking applications. In this post, I break down: 🔹 What synchronous code means (step-by-step execution, blocking nature) 🔹 What asynchronous code means (non-blocking, background execution) 🔹 Why JavaScript needs async behavior 🔹 Real-world examples like API calls & timers 🔹 Problems caused by blocking code 🔹 Visual + intuitive diagrams (execution timeline & task queue) If you're learning JavaScript, this will help you build a strong mental model of how JS works behind the scenes. 🙏 Special thanks to 👉 Hitesh Choudhary Sir 👉 Piyush Garg Sir 👉 Chai Aur Code #JavaScript #WebDevelopment #AsyncJS #Coding #BackendDevelopment #FrontendDevelopment #LearnToCode

One of the most underrated JavaScript features: Destructuring. Not because it's complex,but because once you truly get it, your code never looks the same again. Here's the shift it creates: BEFORE: const a = arr[0]; const b = arr[1]; const name = user.name; const age = user.age; AFTER: const [a, b] = arr; const { name, age } = user; Same logic.But destructuring goes deeper than just shorthand: ✦ Skip indexes in arrays using commas ✦ Rename variables on extraction ✦ Set default values for missing properties ✦ Use ...rest to capture everything remaining ✦ Destructure directly inside function parameters These patterns come up daily, in React, in Node.js, in any codebase that handles real data. I just published a full blog post breaking all of this down with visuals, before/after comparisons, and practical examples. Blog-link: https://lnkd.in/giGUXq7C #JavaScript #JS #WebDev #ProgrammingTips #CleanCode #SoftwareDevelopment

🚨 Ever wondered why your JavaScript code doesn’t freeze even when tasks take time? Here’s the secret: the event loop — the silent hero behind JavaScript’s non-blocking magic. JavaScript is single-threaded, but thanks to the event loop, it can handle multiple operations like a pro. Here’s the simplified flow: ➡️ The Call Stack executes functions (one at a time, LIFO) ➡️ Web APIs handle async tasks like timers, fetch, and DOM events ➡️ Completed tasks move to the Callback Queue (FIFO) ➡️ The Event Loop constantly checks and pushes callbacks back to the stack when it’s free 💡 Result? Smooth UI, responsive apps, and efficient async behavior — all without true multithreading. Understanding this isn’t just theory — it’s the difference between writing code that works and code that scales. 🔥 If you’re working with async JavaScript (Promises, async/await, APIs), mastering the event loop is a game-changer. #JavaScript #WebDevelopment #AsyncProgramming #EventLoop #Frontend #CodingTips

A new write-up from Invaders breaks down Critical protobuf.js flaw turns untrusted schemas into JavaScript code execution. A critical protobuf.js vulnerability allows attacker-controlled protobuf definitions to trigger JavaScript code execution, putting Node.js applications and transitive dependencies at risk when they load untrusted schemas. What stands out here is the practical defender impact and why this kind of issue should be prioritized quickly. Read the full analysis: https://lnkd.in/daHrG72G

⚡ Day 7 — JavaScript Event Loop (Explained Simply) Ever wondered how JavaScript handles async tasks while being single-threaded? 🤔 That’s where the Event Loop comes in. --- 🧠 What is the Event Loop? 👉 The Event Loop manages execution of code, async tasks, and callbacks. --- 🔄 How it works: 1. Call Stack → Executes synchronous code 2. Web APIs → Handle async tasks (setTimeout, fetch, etc.) 3. Callback Queue / Microtask Queue → Stores callbacks 4. Event Loop → Moves tasks to the stack when it’s empty --- 🔍 Example: console.log("Start"); setTimeout(() => { console.log("Timeout"); }, 0); Promise.resolve().then(() => { console.log("Promise"); }); console.log("End"); --- 📌 Output: Start End Promise Timeout --- 🧠 Why? 👉 Microtasks (Promises) run before macrotasks (setTimeout) --- 🔥 One-line takeaway: 👉 “Event Loop decides what runs next in async JavaScript.” --- If you're learning async JS, understanding this will change how you debug forever. #JavaScript #EventLoop #WebDevelopment #Frontend #100DaysOfCode 🚀