Outdated JSX transform

Issues
1

I am seeing the following in DevTool. Is this normal? I am using Plasmic Codegen.

Your app (or one of its dependencies) is using an outdated JSX transform. Update to the modern JSX transform for faster performance: https://react.dev/link/new-jsx-transform

2

Hey @mouthains

It should be fine. Which react version are you using? Could you also share the package.json?

3

I am using React 19 and following is the package.json

{
  "name": "chapter1",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "dev": "next dev --turbopack",
    "build": "next build --turbopack",
    "start": "next start",
    "lint": "eslint"
  },
  "dependencies": {
    "@plasmicapp/cli": "^0.1.359",
    "@plasmicapp/react-web": "^1.0.0",
    "@plasmicpkgs/plasmic-basic-components": "^0.0.272",
    "@plasmicpkgs/plasmic-embed-css": "^0.1.227",
    "@plasmicpkgs/react-aria": "^0.0.175",
    "eslint-config-next": "16.2.2",
    "next": "^16.2.6",
    "react": "^19.2.0",
    "react-dom": "^19.2.0"
  },
  "devDependencies": {
    "@eslint/eslintrc": "^3",
    "@types/node": "^24.6.1",
    "@types/react": "^19.2.0",
    "@types/react-dom": "^19.2.0",
    "eslint": "^9",
    "typescript": "^5"
  }
}
4

I just verified it in a fresh project. It’s just a dev only warning shown for Plasmic generated components which uses a custom jsxRuntime and It should be completely fine in production builds.

More context:
Dev tools such as Turbopack, adds __self and __source props to components in development mode. Plasmic jsxRuntime doesn’t omit them hence it generates that warning. We will review this internally as well to see if we can get rid of this.

5

Thank you for the clarification.