Zag
Finite state machines for accessible JavaScript components
- Write once, use everywhere ?: The component interactions are modelled in a framework agnostic way. We provide adapters for JS frameworks like React, Solid, or Vue.
- Focus on accessibility ♿️: Zag is built with accessibility in mind. We handle many details related to keyboard interactions, focus management, aria roles and attributes.
- Headless ✨: The machine APIs are completely unstyled and gives you the control to use any styling solution you prefer.
- Powered by state machines ?: Zag is built on top of the latest ideas in Statecharts. We don’t follow the SCXML specifications, but we’ve created an API that we think will help us build more complex components fast.
The problem
With the rise of design systems and component-driven development, there’s an endless re-implementation of common component patterns (Tabs, Menu, Modal, etc.) in multiple frameworks.
Most of these implementations seem to be fairly similar in spirit, the differences being around the reactivity and
effects systems for the framework (e.g. useState
, useEffect
in React.js). Framework specific solutions tend to grow
in complexity over time and often become hard to understand, debug, improve or test.
Solution
Zag is a JavaScript API that implements common component patterns using the state machine methodology.
Installation
npm i --save @zag-js/{component}
# or
yarn add @zag-js/{component}
{component}
represents any component machine like dialog (@zag-js/dialog
), tooltip (@zag-js/tooltip
) , etc.
For framework specific solutions, we provide simple wrappers to help you consume the component state machines.
- ⚛️
@zag-js/react
– React hooks for consuming machines in React applications - ?
@zag-js/vue
– Vue composition for consuming machines in Vue applications - ?
@zag-js/solid
– Solid.js utilities for consuming machines in Solid.js applications
Usage
import * as toggle from "@zag-js/toggle"
import { useMachine, useSetup } from "@zag-js/react"
function Example() {
// if you need access to `state` or `send` from machine
const [state, send] = useMachine(toggle.machine)
// setup a unique id and ownerDocument for machine
const ref = useSetup({ send, id: "2" })
// convert machine details into `DOM` props
const api = toggle.connect(state, send)
// consume into components
return (
<button ref={ref} {...api.buttonProps}>
Toggle me
</button>
)
}
Guiding Principles
- All component machine and tests are modelled according to the WAI-ARIA authoring practices
- Write end-to-end tests for every component based on the WAI-ARIA spec. Regardless of the framework, users expect component patterns to work the same way!
- All machines should be light-weight, simple, and easy to understand. Avoid using complex machine concepts like spawn, nested states, etc.
Fun Facts
Zag means to take a sharp change in direction. This clearly describes our approach of using state machines to power the logic behind UI components.
Teasers
-
When you see someone using classic react, vue or solid to build an interactive UI component that exists in Zag, tell them to “zag it!” ⚡️
-
Anyone using Zag will be called a “zagger” ?
-
The feeling you get when you use Zag will be called “zagadat!” ?
-
The Zag community will be called “zag nation” ?
Commands
Build commands
Our build is managed with esbuild and turborepo to provide fast, concurrent builds across the packages.
build:fast
: Build the CJS and ESM versions, without the types.build
: Build the CJS, ESM and DTS files. This is the actual production build that we run in the CI.start
: The command to run when developing for Zag. It runs thebuild:fast
command, watches for changes and rebuilds as needed.
Examples
Since zag is framework agnostic, we need a way to test it within a framework. The examples/
directory includes starter
projects for the frameworks we support.
Make sure to run the
build:fast
orstart
command before this.
start:react
: Starts the Next.js TypeScript projectstart:vue
: Starts the Vue 3 TypeScript projectstart:solid
: Starts the Solid TypeScript project
E2E Tests
We’ve setup end-to-end tests for every machine we built. We use Playwright for testing and we ensure that the component works the same way regardless of the framework.
e2e:react
: Starts the E2E tests for the React projecte2e:vue
: Starts the E2E tests for the Vue projecte2e:solid
: Starts the E2E tests for the Solid project
Contributing new machines/features
gen:machine
: Generates a new machine package in thepackages/
directory. It sets up the required files and structure for new machine.gen:util
: Generates a new utility package in thepackages/utilities
directory.
Other commands
test
: Run the tests for all packageslint
: Lint all packages
Inspirations
- Duplicate code in Chakra UI React and Vue ?
- Thoughts on Pure UI – Guillermo Rauch
- Pure UI Control – Adam Solve
- Material Components Web for inspiring my first prototype
- XState for inspiring the base implementation of the state machine
- Vue.js and Lit for inspiring new patterns in the
machine (
computed
andwatch
)
Contributions
Looking to contribute? Look for the Good First Issue label.
? Bugs
Please file an issue for bugs, missing documentation, or unexpected behavior.
? Feature Requests
Please file an issue to suggest new features. Vote on feature requests by adding a ?. This helps maintainers prioritize what to work on.
License
MIT © Segun Adebayo