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Showing posts with the label React.js

Migrating to React 19: Handling forwardRef and Hydration Breaking Changes

  Upgrading a mature React codebase to v19 is not a silent bump. While the React team has provided codemods, they cannot resolve architectural patterns relying on APIs that have been fundamentally restructured or removed. If you have just upgraded and are staring at a console full of  forwardRef  deprecation warnings,  defaultProps  being ignored, or hydration mismatches causing UI flickers, you are encountering React 19's shift toward standard JavaScript patterns and stricter diffing logic. This post analyzes the root causes of these breaking changes and provides immediate, type-safe solutions to refactor your legacy components. The Root Cause: Simplification and Correctness 1. The Death of  forwardRef In previous versions, function components could not accept a  ref  prop because the  ref  key was stripped off props by the React element creator. To pass a ref through a component, we had to wrap it in  React.forwardRef . This creat...