Revert D5409825: [RN] Convert easy files to Prettier

Differential Revision: D5409825

fbshipit-source-id: f797a40b58bc6bcc6ae53ed820a10ab49d3f10f5

jest/preprocessor.js

@@ -6,7 +6,7 @@
  * LICENSE file in the root directory of this source tree. An additional grant
  * of patent rights can be found in the PATENTS file in the same directory.
  *
- * @format
+ * @flow
  */
 
 /* eslint-env node */
@@ -17,18 +17,22 @@ const babel = require('babel-core');
 const babelRegisterOnly = require('metro-bundler/src/babelRegisterOnly');
 const createCacheKeyFunction = require('fbjs-scripts/jest/createCacheKeyFunction');
 
-const nodeFiles = RegExp(['/local-cli/', '/metro-bundler/'].join('|'));
+const nodeFiles = RegExp([
+  '/local-cli/',
+  '/metro-bundler/',
+].join('|'));
 const nodeOptions = babelRegisterOnly.config([nodeFiles]);
 
 babelRegisterOnly([]);
 
 const transformer = require('metro-bundler/src/transformer.js');
 module.exports = {
-  process(src, file) {
-    if (nodeFiles.test(file)) {
-      // node specific transforms only
-      return babel.transform(src, Object.assign({filename: file}, nodeOptions))
-        .code;
+  process(src/*: string*/, file/*: string*/) {
+    if (nodeFiles.test(file)) { // node specific transforms only
+      return babel.transform(
+        src,
+        Object.assign({filename: file}, nodeOptions)
+      ).code;
     }
 
     return transformer.transform({