Add peer dependency support for React 19

[davidkpiano]

This pull request updates the peer dependencies for React in two packages to ensure compatibility with React 19.0.0.

Updates to peer dependencies:

• packages/xstate-react/package.json: Updated the react peer dependency to include version 19.0.0.
• packages/xstate-store/package.json: Updated the react peer dependency to include version 19.0.0.

---

A couple things we'll have to keep in mind for React 19:

• Render count in strict mode may be different (e.g. 5 instead of 6)
• The way we are testing errors will change: https://react.dev/blog/2024/04/25/react-19#error-handling

[changeset-bot]

🦋 Changeset detected

Latest commit: ef57f54

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@xstate/react	Patch
@xstate/store	Patch

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Click here if you're a maintainer who wants to add another changeset to this PR

[Andarist]

I wonder - what motivated this change now? If I'm not mistaken there is no version out there that's compatible with what is added here, so in some sense - this is going to be a "noop" until React 19 actually gets released.

[hayato94087]

I’m not sure about the details of package fixes, but here’s what I have encountered as a XState user.

The recently released Next.js 15 supports React 19. However, when installing @xstate/react, I have encountered peer dependency errors. Judging from the logs, it seems @xstate/react does not support React 19. To suppress the error message, I needed to downgrade react and react-dom from 19 to 18.

https://nextjs.org/blog/next-15

npx create-next-app@latest next-xstate-15 \
                              --typescript \
                              --eslint \
                              --import-alias "@/*" \
                              --src-dir \
                              --use-pnpm \
                              --tailwind \
                              --app \
                              --use-pnpm \
                              --turbopack
cd next-xstate-15

Install xstate:

pnpm install xstate 

dependencies:
+ xstate 5.18.2

Done in 748ms

When installing @xstate/react, the error message indicates that @xstate/react does not support React 19:

pnpm install @xstate/react

dependencies:
+ @xstate/react 4.1.3

 WARN  Issues with peer dependencies found
.
└─┬ @xstate/react 4.1.3
  ├── ✕ unmet peer react@"^16.8.0 || ^17.0.0 || ^18.0.0": found 19.0.0-rc-69d4b800-20241021
  ├─┬ use-isomorphic-layout-effect 1.1.2
  │ └── ✕ unmet peer react@"^16.8.0 || ^17.0.0 || ^18.0.0": found 19.0.0-rc-69d4b800-20241021
  └─┬ use-sync-external-store 1.2.2
    └── ✕ unmet peer react@"^16.8.0 || ^17.0.0 || ^18.0.0": found 19.0.0-rc-69d4b800-20241021

Done in 744ms

Here is package.json:

{
  ...
  "dependencies": {
    "@xstate/react": "^4.1.3",
    "next": "15.0.1",
    "react": "19.0.0-rc-69d4b800-20241021",
    "react-dom": "19.0.0-rc-69d4b800-20241021",
    "xstate": "^5.18.2"
  },
  ...
}

Here is my repository:

https://github.com/hayato94087/next-xstate-15

[davidkpiano]

@Andarist See here for the original discussion: https://discord.com/channels/795785288994652170/1299849094629560421/1299849094629560421

[Andarist]

The problem is that this doesn't solve this issue:

require('semver').satisfies('19.0.0-rc-69d4b800-20241021', '^19.0.0') // false

To make it work you have to relax this peer dep range even further to allow prereleases