🍦 VanJS: The Smallest Reactive UI Framework in the World

VanJS (abbr. Vanilla JavaScript) is an ultra-lightweight, zero-dependency and unopinionated Reactive UI framework based on pure vanilla JavaScript and DOM. Programming with VanJS feels a lot like React. 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 snippet into VanJS code with our online converter.

VanJS helps you manage state and UI binding 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?

VanJS has the vision to be the scripting language for UI, just like bash is the scripting language for terminal. VanJS empowers frontend engineers, backend engineers, system engineers, data scientists, and anyone else to build comprehensive user interfaces. You can code with VanJS anywhere, any time, and on any device – even on your smartphone! 👏👏👏

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 3rd-party dependencies, no transpiling, no IDE setups. Adding a line to your script or HTML file is all you need to start coding. 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 a very thin layer on top of Vanilla JavaScript and DOM, barely enough to make the DOM manipulation and state binding as ergonomic as (if not more than) React, and it delegates most of work to standard browser APIs implemented in native code. As a result, the bundled size of VanJS is just 1.2kB, which is more than 100 times smaller than most popular UI frameworks:

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

TypeScript Support

VanJS provides first-class support for TypeScript. Simply download the corresponding .d.ts file along with your .js file, and 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.

Easy to Learn

VanJS puts heavy emphasis on the simplicity of the framework. There are only 4 exported functions in the API and feels a lot like React. Because of that, the walkthrough tutorial is the same as the full API referrence, and can be learned within 1 hour for most developers.

Want to Learn More?

• Download and Get Started
• Learn from the Tutorial
• Learn by Examples
• Convert HTML snippet to VanJS code with our online HTML to VanJS Converter
• Want server-side rendering? Check out Mini-Van
• For questions, feedback or general discussions, visit our Discussions page

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.

We're looking for the 1.0 milestone (commitment to API stability) soon, your precious feedback will be greatly appreciated. You can submit your feedback in our Discussions page.

Contact us: [email protected] / Tao Xin

Contributors

Ordered chronologically by first contribution:

• Tao Xin
• Ryan Olson
• Tamotsu Takahashi