🍦 VanJS: The Smallest Reactive UI Framework in the World

Enable everyone to build useful UI apps with a few lines of code, anywhere, any time, on any device.

VanJS is an ultra-lightweight, zero-dependency and unopinionated Reactive UI framework based on pure vanilla JavaScript and DOM. Programming with VanJS feels like building React apps in a scripting language, without JSX. Check-out the Hello World code below:

// Reusable components can be just pure vanilla JavaScript functions.
// Here we capitalize the first letter to follow React conventions.
const Hello = () => div(
  p("👋Hello"),
  ul(
    li("🗺️World"),
    li(a({href: "https://vanjs.org/"}, "🍦VanJS")),
  ),
)

van.add(document.body, Hello())
// Alternatively, you can write:
// document.body.appendChild(Hello())

Try on jsfiddle

You can convert any HTML or MD snippet into VanJS code with our online converter.

VanJS helps you manage states and UI bindings as well, with a more natural API:

const Counter = () => {
  const counter = van.state(0)
  return div(
    "❤️ ", counter, " ",
    button({onclick: () => ++counter.val}, "👍"),
    button({onclick: () => --counter.val}, "👎"),
  )
}

van.add(document.body, Counter())

Try on jsfiddle

Why VanJS?

Reactive Programming without React/JSX

Declarative DOM tree composition, reusable components, reactive state binding - VanJS offers every good aspect that React does, but without the need of React, JSX, transpiling, virtual DOM, or any hidden logic. Everything is built with simple JavaScript functions and DOM.

Grab 'n Go

No installation, no configuration, no dependencies, no transpiling, no IDE setups. Adding a line to your script or HTML file is all you need to start coding. And any code with VanJS can be pasted and executed directly in your browser's developer console. VanJS allows you to focus on the business logic of your application, rather than getting bogged down in frameworks and tools.

Ultra-Lightweight

VanJS is the smallest reactive UI framework in the world, with just 0.9kB in the gzipped minified bundle. It's 50~100 times smaller than most popular alternatives. Guess what you can get from this 0.9kB framework? All essential features of reactive UI programming - DOM templating, state, state binding, state derivation, effect, SPA, client-side routing and even hydration!

Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.

-- Antoine de Saint-Exupéry, Airman's Odyssey

Easy to Learn

Simplicity at its core. 5 major functions (van.tags, van.add, van.state, van.derive, van.hydrate) + 4 auxiliary functions (van.tagsNS, van._, van.val, van.oldVal). The the entire tutorial plus the API reference is just one single web page, and can be learned within 1 hour for most developers.

Performance

VanJS is among the fastest web frameworks, according to the results by krausest/js-framework-benchmark. For SSR, Mini-Van is 1.75X to 2.25X more efficient compared to React.

TypeScript Support

VanJS provides first-class support for TypeScript. With the .d.ts file in place, you'll be able to take advantage of type-checking, IntelliSense, large-scale refactoring provided by your preferred development environment. Refer to the Download Table to find the right .d.ts file to work with.

Want to Learn More?

Get Started (CDN, NPM or local download)
Learn from the Tutorial
Learn by Examples (and also Community Examples)
Convert HTML or MD snippet to VanJS code with our online HTML/MD to VanJS Converter
Check out VanUI - A collection of grab 'n go reusable UI components for VanJS
Want server-side rendering? Check out Mini-Van and Hydration (the entire vanjs.org site is built on top of Mini-Van)
For questions, feedback or general discussions, visit our Discussions page
How did VanJS get its name?

IDE Plug-ins

VS Code Extension

Support & Feedback

🙏 VanJS aims to build a better world by reducing the entry barrier for UI programming, with no intention or plan on commercialization whatsoever. If you find VanJS interesting, or could be useful for you some day, please consider starring the project. It takes just a few seconds but your support means the world to us and helps spread VanJS to a wider audience.

In the name of Vanilla of the House JavaScript, the First of its name, Smallest Reactive UI Framework, 0.9kB JSX-free Grab 'n Go Library, Scripting Language for GUI, ChatGPT-Empowered Toolkit, by the word of Tao of the House Xin, Founder and Maintainer of VanJS, I do hereby grant you the permission of VanJS under MIT License.

Community Add-ons

VanJS can be extended via add-ons. Add-ons add more features to VanJS and/or provide an alternative styled API. Below is a curated list of add-ons built by VanJS community:

van_dml.js: adds a a new flavour of composition to VanJS. Author: Eckehard.
van-jsx: a JSX wrapper for VanJS, for people who like the JSX syntax more. Author: cqh963852.

Contributors (29)

If I miss anyone's contribution here, apologies for my oversight 🙏, please comment on #87 to let me know.

Emoji key

_{Tao Xin} 🎨 💻 📖 💡	_{Ryan Olson} 🖋	_{Tamotsu Takahashi} 💻	_icecream17 💻	_enpitsulin 💡 💻	_{Elliot Ford} 💻	_andrewgryan 🎨 💻 🐛
_FredericH 💡 💻	_ebraminio 💻 ⚠️	_Eckehard 💻 🔌	_{Austin Merrick} 💻 🤔 🎨	_{Lee Byonghun} 💻	_{caputdraconis} 💻	_{Achille Lacoin} 💻
_cqh 💻 🔌	_awesome 📹	_artydev 💡 💬	_{Neven DREAN} 💡 🐛	_{Stephen Handley} 💡	_{Ionut Stoica} 🤔	_{Rasmus Schultz} 🤔
_cloudspeech 🤔	_{Daniel Upshaw} 🔌	_barrymun 💡	_{Giulio Malventi} 🖋	_{Yahia Berashish} 🐛 💻 🔌 🤔	_{Phil Schumann} 🐛	_{Raphaël Gauthier} 💻 🔌
_Nail 💻 🔌