react19-source-patterns

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Reference for React 19 source-file migration patterns, including API changes, ref handling, and context updates. npx skills add https://github.com/github/awesome-copilot --skill react19-source-patterns Download ZIPGitHub36.2k

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 String refs this.refs.x → createRef() → 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:

// NOTE: React 19 no longer runs propTypes validation at runtime.
// PropTypes kept for documentation and IDE tooling only.

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.