code: function(string) {
      var result = parseInt(string, 10);
  
      if (ICAL.helpers.isStrictlyNaN(result)) {
        throw new Error(
          'Could not extract integer from "' + string + '"'
        );
      }
  
      return result;
    }
docs: Parses a string value that is expected to be an integer, when the valid is
  not an integer throws a decoration error.
  
  @param {String} string     Raw string input
  @return {Number}           Parsed integer