JS Visualizer

What it does

Watch JavaScript execute step by step. See the call stack, Web APIs, microtask & task queues, and event loop animate in real time. Finally understand why Promises fire before setTimeout and how async/await actually works. ✦ Breakpoints, step mode, speed control ✦ 20+ examples · Side-by-side comparison · Share via URL ✦ Spec-linked step explanations Free. No signup.

Free interactive JavaScript visualizer. Step through code line-by-line and watch the call stack, Web APIs, microtask queue, event loop, and memory graph come to life. Master async/await, Promises, closures, and the JS runtime.

JS Visualizer is a free interactive JavaScript visualizer that simulates the JavaScript runtime in real time. Step through code line-by-line and watch the call stack , Web APIs , task queue , microtask queue , event loop , and a force-directed memory graph animate as your code executes. Built for developers learning async/await, Promises, closures, generators, classes, and the event loop, JS Visualizer turns abstract runtime behavior into something you can watch and reason about. Synchronous execution, call stack, Promises, microtasks, timers, event loop, async/await, advanced patterns, error handling, Web APIs, hoisting & TDZ, scope & closures, this binding, type coercion, Map & Set,…from jsvisualizer.bytefront.dev

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  JavaScript Event Loop VisualizerJan 2026 · js-event-loop-visualizer-one.vercel.app · ▲8

  Master async JavaScript with interactive visualization

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  JS library to make your website instant2014 · ▲426

  http://instantclick.io/ It seems the internet architecture won't bring us instant websites anytime soon. So here is a hack. I released this JS library last month (today is version 2.0 release, fixing v1.0's rough edges), it makes use of HTML5's pushState and preloading to make a website instant. It works like this: before clicking on a link, you'll hover over it. And there's a delay of 200-300 ms between these two events. InstantClick uses this delay to preload a page, when you click on a link it will display instantly in most case. (You can test on the website.) That's…

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  JS Brain Teasers2025 · jsbrainteasers.com · ▲8

  Learn the javascript event loop in a new and fun way

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  Pts.js – A library for visualization and creative coding2018 · ptsjs.org · ▲611

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  30 seconds of code2018 · github.com · ▲252

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  Hi HN, I’m a fullstack developer, and honestly, I’ve lost count of how many side projects I’ve worked on over the years. But one idea kept coming back to me: a different kind of email client. It first came to me in 2014: “What if we could handle emails more like conversations?” Every year, I’d revisit this concept in my “Build Notes.” Ten years later, no one had built exactly what I had in mind — so I finally decided to do it myself. That’s how Talanoa was born. I wanted something focused on people, not timelines. I was tired of marking messages as unread just to remember to reply later, or…

  Dev tools · 21d ago · talanoa.email

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  Life & fun · May 2026 · github.com

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