React Guideline: Patterns — Render props for flexibility. Description: Share code via render prop pattern. Do: Render prop for customizable rendering. Don't: Duplicate logic across components. Good Example: <DataFetcher render={data => ...}/>. Bad Example: Copy paste fetch logic. Severity: Low. Docs: https://react.dev/reference/react/cloneElement#passing-data-with-a-render-prop.