code: function (fileName, fileTypes) {
      var _fileNameStr = fileName.substring(fileName.lastIndexOf('.') + 1, fileName.length).toLowerCase();
      if (fileTypes.indexOf(_fileNameStr) > -1) { return true }
      return false
    }
docs: Check fileName's type in the fileTypes
  @param fileName String
  @param fileTypes Array []
  @return Boolean {true, false}