However, there is use case where the caller just needs a static ref at component level to wrap a dynamic value: for example, I need to read/write a static ref in rendering path (keep it in-sync with the current render context value)
In another word, the argument could be "a need to read/sync a "render context" value into a static variable attached to the functional component", + the "ref" value is not use in the "return" of the functional component
const { componentId, renderId } = useContext(componentContext);
const context = { componentId, renderId } <--- dynamic
const contextRef = useRef(context); <--- static
contextRef.current = context;
useQuery({
context: contextRef <--- static ref to avoid equal check, the ref value is only used for logging
})
Summary
In the doc for ref https://react.dev/reference/react/useRef#caveats, it calls out to not read/write ref in rendering phase without a very clear "bad example"
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However, there is use case where the caller just needs a static ref at component level to wrap a dynamic value: for example, I need to read/write a static ref in rendering path (keep it in-sync with the current render context value)
In another word, the argument could be "a need to read/sync a "render context" value into a static variable attached to the functional component", + the "ref" value is not use in the "return" of the functional component
e.g. https://github.com/apollographql/apollo-client/issues/11835
and there are popular library like useLatest implemented by writing ref in render path
Can we remove or update the caveat to make it more clear? E.g. adding