Complete json format

lib/json/encodeFile.js

@@ -6,8 +6,13 @@
     @return {Object}
 */
 function encodeFileToJson(file) {
+    var filePath = file.getPath();
+    if (!filePath) {
+        return undefined;
+    }
+
     return {
-        path: file.getPath(),
+        path: filePath,
         mtime: file.getMTime(),
         type: file.getType()
     };