JavaScript Set size with 0, -0, +0 values

21 Feb 2026 -> Started arrays and learned how to create and access elements. -> Practiced basic array methods like push() and pop(). #javascript #frontend #LearninginPublic #DevJourney

If you understand this, you understand async JavaScript. There are TWO important queues: 1️⃣ Microtask Queue 2️⃣ Macrotask Queue Example: console.log("Start"); setTimeout(() => console.log("Timeout"), 0); Promise.resolve().then(() => console.log("Promise")); console.log("End"); Output: Start End Promise Timeout Why? Execution order: Run synchronous code Empty Microtask queue Take one Macrotask Repeat Microtasks include: • Promise callbacks • queueMicrotask Macrotasks include: • setTimeout • setInterval • I/O Promise always runs before setTimeout. This is critical when debugging race conditions. #javascript #eventloop #webdevelopment #frontend

Ever noticed this in JavaScript? 👀 -------- console.log("start"); setTimeout(() => console.log("timeout")); Promise.resolve().then(() => console.log("promise")); console.log("end"); -------- Most developers expect setTimeout to run first. But the output is: -------- start end promise timeout -------- Why? Because Promises go into the Microtask Queue, while setTimeout goes into the Macrotask Queue. The JavaScript event loop always processes all microtasks before the next macrotask once the call stack is empty. Execution order becomes: 1️⃣ Synchronous code 2️⃣ Microtasks (Promise, queueMicrotask) 3️⃣ Macrotasks (setTimeout, setInterval, DOM events) So even setTimeout(fn, 0) will run after Promise callbacks. Understanding this small detail helps explain many tricky async bugs in real applications. #javascript #webdevelopment #frontend #async #eventloop

🚀 30 Days of JavaScript Tricky Questions – Day 1 Let’s start with async / await + event loop 🧠 async function foo() { console.log('A'); setTimeout(() => console.log('B'), 0); await Promise.resolve(); console.log('C'); } foo(); console.log('D'); ❓ What will be the output and why? 💬 Drop your answer in the comments #JavaScript #JSInterview #AsyncJavaScript #FrontendDeveloper #WebDevelopment #30DaysOfJavaScript

Day 8 of #100DaysOfCode Built a Stopwatch using JavaScript. Features: ⏱️ Start / Stop functionality. 🔄 Reset timer 📊 Real-time time tracking Continuing to improve my JavaScript fundamentals through small projects. Git-Hub Repo Link: https://lnkd.in/geZqCnQ9 #JavaScript #WebDevelopment #Frontend

💡 var vs let vs const – Most Confusing Topic for Beginners 🚨 If you still use var in 2026… we need to talk. Difference: 🔹 var Function scoped Can redeclare Can update 🔹 let Block scoped Can update Cannot redeclare in same scope 🔹 const Block scoped Cannot update Cannot redeclare Golden Rule: 👉 Use const by default 👉 Use let when value changes 👉 Avoid var Which one do you use most? 👇 #JavaScript #Frontend #CodingTips

Things wish knew when I started frontend: -The browser is your best debugging tool. Learn DevTools deeply. - CSS isn't broken. You just don't understand the box model yet. - JavaScript fundamentals matter more than any framework. -Your first 10 projects will be ugly. Ship them anyway. Number 4 is the one most people skip. #Frontend #WebDevelopment #JavaScript #CSs #DevLife #SoftwareEngineering Serah ABIJO

🧠 JavaScript Closure Challenge What will be the output? for (var i = 0; i < 3; i++) { setTimeout(() => { console.log(i); }, 100); } Options: A) 0 1 2 B) 3 3 3 C) 1 2 3 D) 0 0 0 Can you explain why? 👀 #javascript #frontend #codingchallenge

Closure behavior with asynchronous code Consider: for (var i = 0; i < 3; i++) { setTimeout(() => console.log(i), 1000); } Output: 3 3 3 Reason: var is function scoped. All callbacks reference the same variable. When loop finishes: i = 3 Solution using let: for (let i = 0; i < 3; i++) { setTimeout(() => console.log(i), 1000); } Output: 0 1 2 let creates new binding each iteration. Understanding lexical scope is essential for predictable behavior. #javascript #frontend