Set up use-sync-external-store package

ReactVersions.js

@@ -47,6 +47,7 @@ const experimentalPackages = [
  'react-fs',
  'react-pg',
  'react-server-dom-webpack',
+ 'use-sync-external-store',
 ];
 
 module.exports = {

packages/use-sync-external-store/README.md

@@ -0,0 +1,5 @@
+# use-sync-external-store
+
+Backwards compatible shim for React's `useSyncExternalStore`. Works with any React that supports hooks.
+
+Until `useSyncExternalStore` is documented, refer to https:/reactwg/react-18/discussions/86

packages/use-sync-external-store/index.js

@@ -0,0 +1,12 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+'use strict';
+
+export * from './src/useSyncExternalStore';

packages/use-sync-external-store/npm/index.js

@@ -0,0 +1,7 @@
+'use strict';
+
+if (process.env.NODE_ENV === 'production') {
+ module.exports = require('./cjs/use-sync-external-store.production.min.js');
+} else {
+ module.exports = require('./cjs/use-sync-external-store.development.js');
+}

packages/use-sync-external-store/package.json

@@ -0,0 +1,21 @@
+{
+ "name": "use-sync-external-store",
+ "description": "Backwards compatible shim for React's useSyncExternalStore. Works with any React that supports hooks.",
+ "version": "0.0.1",
+ "repository": {
+ "type": "git",
+ "url": "https:/facebook/react.git",
+ "directory": "packages/use-sync-external-store"
+ },
+ "files": [
+ "LICENSE",
+ "README.md",
+ "build-info.json",
+ "index.js",
+ "cjs/"
+ ],
+ "license": "MIT",
+ "peerDependencies": {
+ "react": "^16.8.0 || ^17.0.0"
+ }
+}

packages/use-sync-external-store/src/__tests__/useSyncExternalStore-test.js

@@ -0,0 +1,14 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @emails react-core
+ */
+
+'use strict';
+
+describe('useSyncExternalStore', () => {
+ test('TODO', () => {});
+});

packages/use-sync-external-store/src/useSyncExternalStore.js

@@ -0,0 +1,12 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow
+ */
+
+export function useSyncExternalStore() {
+ throw new Error('Not yet implemented');
+}

scripts/rollup/bundles.js

@@ -684,6 +684,15 @@ const bundles = [
  externals: ['react'],
  },
 
+ /******* Shim for useSyncExternalState *******/
+ {
+ bundleTypes: [NODE_DEV, NODE_PROD],
+ moduleType: ISOMORPHIC,
+ entry: 'use-sync-external-store',
+ global: 'useSyncExternalStore',
+ externals: ['react'],
+ },
+
  /******* React Scheduler (experimental) *******/
  {
  bundleTypes: [