[compiler] Compile lib (#31165)

Add and compile a simple hook with rollup and babel.
---
[//]: # (BEGIN SAPLING FOOTER)
Stack created with [Sapling](https://sapling-scm.com). Best reviewed
with [ReviewStack](https://reviewstack.dev/facebook/react/pull/31165).
* #31167
* #31166
* __->__ #31165

compiler/fixtures/runtime-compat/lib/babel.config.js

@@ -0,0 +1,10 @@
+const plugins = [
+  [
+    'babel-plugin-react-compiler',
+    {
+      target: '18',
+    },
+  ],
+];
+
+module.exports = {plugins};

compiler/fixtures/runtime-compat/lib/index.js

@@ -1 +1,13 @@
-throw new Error('Not implemented yet');
+import {useState, useEffect} from 'react';
+
+export function useTime() {
+  const [time, setTime] = useState(() => new Date());
+  useEffect(() => {
+    const id = setInterval(() => {
+      setTime(new Date());
+    }, 1000);
+    return () => clearInterval(id);
+  }, []);
+
+  return time;
+}

compiler/fixtures/runtime-compat/lib/package.json

@@ -2,18 +2,31 @@
   "name": "runtime-compat-lib",
   "version": "0.0.0",
   "description": "Testing ground for libraries compiled with React Compiler",
-  "main": "index.js",
+  "main": "dist/index.js",
   "scripts": {
+    "build": "rimraf dist && rollup --config --bundleConfigAsCjs",
     "test": "echo 'no tests'"
   },
   "license": "MIT",
   "devDependencies": {
     "@babel/cli": "^7.25.7",
     "@babel/core": "^7.25.7",
     "@babel/preset-env": "^7.25.7",
-    "babel-plugin-react-compiler": "0.0.0-experimental-58c2b1c-20241009"
+    "@rollup/plugin-babel": "^6.0.4",
+    "@rollup/plugin-json": "^6.1.0",
+    "babel-plugin-react-compiler": "0.0.0-experimental-58c2b1c-20241009",
+    "@rollup/plugin-terser": "^0.4.4",
+    "react": "19.0.0-beta-26f2496093-20240514",
+    "react-dom": "19.0.0-beta-26f2496093-20240514",
+    "rimraf": "5",
+    "rollup": "^4.22.4",
+    "rollup-plugin-banner2": "^1.2.3",
+    "rollup-plugin-prettier": "^4.1.1"
   },
   "dependencies": {
     "react-compiler-runtime": "0.0.0-experimental-8d8e73f-20241009"
+  },
+  "peerDependencies": {
+    "react": "^18 || ^19"
   }
 }

compiler/fixtures/runtime-compat/lib/rollup.config.js

@@ -0,0 +1,51 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import json from '@rollup/plugin-json';
+import terser from '@rollup/plugin-terser';
+import prettier from 'rollup-plugin-prettier';
+import banner2 from 'rollup-plugin-banner2';
+import babel from '@rollup/plugin-babel';
+
+const ROLLUP_CONFIG = {
+  input: 'index.js',
+  output: {
+    file: 'dist/index.js',
+    format: 'esm',
+    sourcemap: false,
+    exports: 'named',
+  },
+  plugins: [
+    json(),
+    babel({babelHelpers: 'bundled'}),
+    terser({
+      format: {
+        comments: false,
+      },
+      compress: false,
+      mangle: false,
+    }),
+    prettier(),
+    banner2(
+      () => `/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @lightSyntaxTransform
+ * @noflow
+ * @nolint
+ * @preventMunge
+ * @preserve-invariant-messages
+ */
+`
+    ),
+  ],
+};
+
+export default ROLLUP_CONFIG;