skills/composition-patterns/rules/state-decouple-implementation.md
The provider component should be the only place that knows how state is managed. UI components consume the context interface—they don't know if state comes from useState, Zustand, or a server sync.
Incorrect (UI coupled to state implementation):
function ChannelComposer({ channelId }: { channelId: string }) {
// UI component knows about global state implementation
const state = useGlobalChannelState(channelId)
const { submit, updateInput } = useChannelSync(channelId)
return (
<Composer.Frame>
<Composer.Input
value={state.input}
onChange={(text) => sync.updateInput(text)}
/>
<Composer.Submit onPress={() => sync.submit()} />
</Composer.Frame>
)
}
Correct (state management isolated in provider):
// Provider handles all state management details
function ChannelProvider({
channelId,
children,
}: {
channelId: string
children: React.ReactNode
}) {
const { state, update, submit } = useGlobalChannel(channelId)
const inputRef = useRef(null)
return (
<Composer.Provider
state={state}
actions={{ update, submit }}
meta={{ inputRef }}
>
{children}
</Composer.Provider>
)
}
// UI component only knows about the context interface
function ChannelComposer() {
return (
<Composer.Frame>
<Composer.Header />
<Composer.Input />
<Composer.Footer>
<Composer.Submit />
</Composer.Footer>
</Composer.Frame>
)
}
// Usage
function Channel({ channelId }: { channelId: string }) {
return (
<ChannelProvider channelId={channelId}>
<ChannelComposer />
</ChannelProvider>
)
}
Different providers, same UI:
// Local state for ephemeral forms
function ForwardMessageProvider({ children }) {
const [state, setState] = useState(initialState)
const forwardMessage = useForwardMessage()
return (
<Composer.Provider
state={state}
actions={{ update: setState, submit: forwardMessage }}
>
{children}
</Composer.Provider>
)
}
// Global synced state for channels
function ChannelProvider({ channelId, children }) {
const { state, update, submit } = useGlobalChannel(channelId)
return (
<Composer.Provider state={state} actions={{ update, submit }}>
{children}
</Composer.Provider>
)
}
The same Composer.Input component works with both providers because it only
depends on the context interface, not the implementation.