Move bundle output formats to their own files

Reviewed By: tadeuzagallo

Differential Revision: D2702834

fb-gh-sync-id: fca308c5078a11924e071077822fb77d762bd564

local-cli/bundle/output/writeFile.js

@@ -0,0 +1,25 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * 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.
+ */
+'use strict';
+
+const fs = require('fs');
+const Promise = require('promise');
+
+function writeFile(file, data, encoding) {
+  return new Promise((resolve, reject) => {
+    fs.writeFile(
+      file,
+      data,
+      encoding,
+      error => error ? reject(error) : resolve()
+    );
+  });
+}
+
+module.exports = writeFile;