code: function errorMessage(fileError) {
          var msg = '';
          switch (fileError.code) {
              case FileError.NOT_FOUND_ERR:
                  msg = 'File not found';
                  break;
              case FileError.SECURITY_ERR:
                  // You may need the --allow-file-access-from-files flag
                  // if you're debugging your app from file://.
                  msg = 'Security error';
                  break;
              case FileError.ABORT_ERR:
                  msg = 'Aborted';
                  break;
              case FileError.NOT_READABLE_ERR:
                  msg = 'File not readable';
                  break;
              case FileError.ENCODING_ERR:
                  msg = 'Encoding error';
                  break;
              case FileError.NO_MODIFICATION_ALLOWED_ERR:
                  msg = 'File not modifiable';
                  break;
              case FileError.INVALID_STATE_ERR:
                  msg = 'Invalid state';
                  break;
              case FileError.SYNTAX_ERR:
                  msg = 'Syntax error';
                  break;
              case FileError.INVALID_MODIFICATION_ERR:
                  msg = 'Invalid modification';
                  break;
              case FileError.QUOTA_EXCEEDED_ERR:
                  // You may need the --allow-file-access-from-files flag
                  // if you're debugging your app from file://.
                  msg = 'Quota exceeded';
                  break;
              case FileError.TYPE_MISMATCH_ERR:
                  msg = 'Type mismatch';
                  break;
              case FileError.PATH_EXISTS_ERR:
                  msg = 'File already exists';
                  break;
              default:
                  msg = 'Unknown FileError code (code= ' + fileError.code + ', type=' + typeof(fileError) + ')';
                  break;
          }
          return msg;
      }
docs: Private API helper functions and variables hidden within this function scope