Reference for React 19 source-file migration patterns, including API changes, ref handling, and context updates.

React 19 Source Migration Patterns Reference for every source file migration required for React 19. Quick Reference Table Pattern Action Reference ReactDOM.render(...) → createRoot().render() See references/api migrations.md ReactDOM.hydrate(...) → hydrateRoot(...) See references/api migrations.md unmountComponentAtNode → root.unmount() Inline fix ReactDOM.findDOMNode → direct ref Inline fix forwardRef(...) wrapper → ref as direct prop See references/api migrations.md Component.defaultProps = {} → ES6 default params See references/api migrations.md useRef() no arg → useRef(null) Inline fix add null Legacy Context → createContext [→ api migrations.md legacy context](references/api migrations.md legacy context) String refs this.refs.x → createRef() [→ api migrations.md string refs](references/api migrations.md string refs) import React from 'react' (unused) Remove Only if no React. usage in file PropTypes Rule Do not remove .propTypes assignments. The prop types package still works as a standalone validator. React 19 only removes the built in runtime checking from the React package the package itself remains valid. Add this comment above any .propTypes block: Read the Reference For full before/after code for each migration, read references/api migrations.md . It contains the complete patterns including edge cases for forwardRef with useImperativeHandle , defaultProps null vs undefined behavior, and legacy context provider/consumer cross file migrations.

react19-source-patterns