react19-source-patterns

Original：🇺🇸 English

Translated

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

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Sourcegithub/awesome-copilot

Added on2026-04-10

NPX Install

npx skill4agent add github/awesome-copilot react19-source-patterns

SKILL.md Content

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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:

jsx

// 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.