feat(react-transform-rolldown): add native rolldown plugin

.changeset/small-peaches-wave.md

@@ -0,0 +1,5 @@
+---
+"@preact/signals-react-transform-rolldown": minor
+---
+
+Add a native Rolldown plugin for the React Signals transform so Rolldown and Vite Rolldown builds can automatically subscribe React components and hooks to signal reads.

.github/workflows/main.yml

@@ -53,4 +53,4 @@ jobs:
         working-directory: packages/react
         run: |
           pnpm i react@16 react-dom@16 react-router-dom@5
-          pnpm -w exec cross-env COVERAGE=true MINIFY=true vitest run packages/react
+          pnpm -w exec cross-env COVERAGE=true MINIFY=true vitest run ./packages/react/

package.json

@@ -4,7 +4,7 @@
   "scripts": {
     "prebuild": "shx rm -rf packages/*/dist/",
     "build": "run-p build:* && pnpm _build:devtools-ui",
-    "_build": "microbundle --raw --globals @preact/signals-core=preactSignalsCore,preact/hooks=preactHooks,@preact/signals-react/runtime=reactSignalsRuntime",
+    "_build": "microbundle --raw --globals @preact/signals-core=preactSignalsCore,preact/hooks=preactHooks,@preact/signals-react/runtime=reactSignalsRuntime,rolldown/utils=rolldownUtils",
     "build:core": "pnpm _build --cwd packages/core && pnpm postbuild:core",
     "build:debug": "pnpm _build --cwd packages/debug && pnpm postbuild:debug",
     "build:devtools-adapter": "pnpm _build --cwd packages/devtools-adapter && pnpm postbuild:devtools-adapter",
@@ -16,6 +16,7 @@
     "build:react-utils": "pnpm _build --cwd packages/react/utils && pnpm postbuild:react-utils",
     "build:react-runtime": "pnpm _build --cwd packages/react/runtime && pnpm postbuild:react-runtime",
     "build:react-transform": "pnpm _build --no-compress --cwd packages/react-transform",
+    "build:react-transform-rolldown": "pnpm _build --no-compress --cwd packages/react-transform-rolldown --external \"rolldown,rolldown/utils,rolldown-string\"",
     "build:preact-transform": "pnpm _build --no-compress --cwd packages/preact-transform",
     "postbuild:core": "shx mv -f  packages/core/dist/index.d.ts  packages/core/dist/signals-core.d.ts",
     "postbuild:debug": "shx mv -f packages/debug/dist/debug/src/index.d.ts packages/debug/dist/signals-debug.d.ts",

packages/react-transform-rolldown/CHANGELOG.md

@@ -0,0 +1 @@
+# @preact/signals-react-transform-rolldown

packages/react-transform-rolldown/README.md

@@ -0,0 +1,56 @@
+# Signals React Transform Rolldown Plugin
+
+> A Rolldown plugin to transform React components so they automatically subscribe to Preact Signals.
+
+This package applies the React Signals transform during Rolldown builds with Rolldown's native magic string pipeline, so React components and hooks can subscribe to signal reads without wiring Babel up manually.
+
+## Installation
+
+```sh
+npm i --save-dev @preact/signals-react-transform-rolldown
+npm i react @preact/signals-react
+```
+
+## Usage
+
+```ts
+import reactSignalsTransform from "@preact/signals-react-transform-rolldown";
+
+export default {
+	plugins: [
+		reactSignalsTransform({
+			mode: "auto",
+		}),
+	],
+};
+```
+
+## Options
+
+This plugin forwards the same options as `@preact/signals-react-transform`:
+
+- `mode`
+- `importSource`
+- `detectTransformedJSX`
+- `experimental`
+
+Example:
+
+```ts
+reactSignalsTransform({
+	detectTransformedJSX: true,
+	experimental: {
+		debug: true,
+	},
+});
+```
+
+## Notes
+
+- Run it before other JSX transforms.
+- The generated code imports `useSignals` from `@preact/signals-react/runtime` by default.
+- When your code is already compiled to `react/jsx-runtime` or `React.createElement`, enable `detectTransformedJSX`.
+
+## License
+
+`MIT`, see the [LICENSE](../../LICENSE) file.

packages/react-transform-rolldown/package.json

@@ -0,0 +1,78 @@
+{
+  "name": "@preact/signals-react-transform-rolldown",
+  "version": "0.0.0",
+  "license": "MIT",
+  "description": "Rolldown plugin for the React Signals transform",
+  "keywords": [
+    "plugin",
+    "react",
+    "rolldown",
+    "rolldown-plugin",
+    "signals"
+  ],
+  "authors": [
+    "The Preact Authors (https://github.com/preactjs/signals/contributors)"
+  ],
+  "repository": {
+    "type": "git",
+    "url": "https://github.com/preactjs/signals",
+    "directory": "packages/react-transform-rolldown"
+  },
+  "bugs": "https://github.com/preactjs/signals/issues",
+  "homepage": "https://preactjs.com",
+  "funding": {
+    "type": "opencollective",
+    "url": "https://opencollective.com/preact"
+  },
+  "main": "dist/index.js",
+  "module": "dist/index.mjs",
+  "types": "dist/index.d.ts",
+  "source": "src/index.ts",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.mjs",
+      "require": "./dist/index.js"
+    }
+  },
+  "files": [
+    "dist",
+    "src",
+    "CHANGELOG.md",
+    "LICENSE",
+    "README.md"
+  ],
+  "scripts": {
+    "build": "microbundle --raw --no-compress --external \"rolldown,rolldown/utils,rolldown-string\" --globals \"rolldown/utils=rolldownUtils\"",
+    "test": "cd ../.. && pnpm vitest run ./packages/react-transform-rolldown/test/node/*.test.ts",
+    "prepublishOnly": "cd ../.. && pnpm build:react-transform-rolldown"
+  },
+  "dependencies": {
+    "rolldown-string": "^0.3.0"
+  },
+  "peerDependencies": {
+    "@preact/signals-react": "^3.9.1",
+    "react": "^16.14.0 || 17.x || 18.x || 19.x",
+    "rolldown": "^1.0.0-rc.9",
+    "vite": "^8.0.0"
+  },
+  "peerDependenciesMeta": {
+    "vite": {
+      "optional": true
+    }
+  },
+  "devDependencies": {
+    "@preact/signals-core": "workspace:*",
+    "@preact/signals-react": "workspace:^3.9.1",
+    "@types/react": "18.0.18",
+    "@types/react-dom": "18.0.6",
+    "prettier": "^3.0.0",
+    "react": "^18.2.0",
+    "react-dom": "^18.2.0",
+    "rolldown": "^1.0.0-rc.9"
+  },
+  "publishConfig": {
+    "access": "public",
+    "provenance": true
+  }
+}