React19 Source Patterns

A migration reference for upgrading React codebases to version 19, covering every breaking API change at the source file level. You get a quick lookup table for the common replacements (ReactDOM.render to createRoot, forwardRef as direct props, defaultProps to ES6 defaults) plus links to full before/after code for edge cases. Smart call keeping the PropTypes note, since people still use that package standalone even though React stopped validating it. If you're doing a React 19 upgrade and hitting deprecation warnings, this gives you the exact syntax changes without digging through release notes.

skills.sh installs: 993
GitHub stars: 41K
last updated: Aug 21, 2026

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Install

$ npx -y skills add github/awesome-copilot --skill react19-source-patterns --agent claude-code

Installs into .claude/skills of the current project.

Files

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