Migrate packageMetadata

Summary: _typescript_

Reviewed By: danielbuechele

Differential Revision: D16782045

fbshipit-source-id: cfbabc036eb707f76a375f451ccc831b25c6d462

src/utils/packageMetadata.tsx

@@ -0,0 +1,36 @@
+/**
+ * Copyright 2018-present Facebook.
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ * @format
+ */
+
+import electron from 'electron';
+import lodash from 'lodash';
+import isProduction from './isProduction';
+import path from 'path';
+import fs from 'fs';
+import {promisify} from 'util';
+
+const getPackageJSON = async () => {
+  const base =
+    isProduction() && electron.remote
+      ? electron.remote.app.getAppPath()
+      : process.cwd();
+  const content = await promisify(fs.readFile)(
+    path.join(base, 'package.json'),
+    'utf-8',
+  );
+  return JSON.parse(content);
+};
+
+export const readCurrentRevision: () => Promise<
+  string | undefined
+> = lodash.memoize(async () => {
+  // This is provided as part of the bundling process for headless.
+  if (global.__REVISION__) {
+    return global.__REVISION__;
+  }
+  const json = await getPackageJSON();
+  return json.revision;
+});