Add types to scripts and config files

Summary:
Now that we have some TypeScript infra set up, move scripts (mainly the benchmarking one) and config files to TypeScript.

Starts to move away a bit from the magic globals used in the JS environment.

Differential Revision: D45511176

fbshipit-source-id: 541b967a276d2894e68b505169fc69096589d8c4

javascript/jest.config.ts

@@ -0,0 +1,17 @@
+/**
+ * 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.
+ *
+ * @format
+ */
+
+import type { Config } from "jest";
+
+const config: Config = {
+  setupFiles: ["./jest.setup.ts"],
+  testRegex: "/tests/.*\\.test\\.[jt]s$",
+};
+
+export default config;