Function addDivider

static/bootstrap-select-1.13.18/js/bootstrap-select.js:1509–1525

(config)

      var selectOptions = this.$element[0].querySelectorAll('select > *' + optionSelector);

      function addDivider (config) {
        var previousData = mainData[mainData.length - 1];

        // ensure optgroup doesn't create back-to-back dividers
        if (
          previousData &&
          previousData.type === 'divider' &&
          (previousData.optID || config.optID)
        ) {
          return;
        }

        config = config || {};
        config.type = 'divider';

        mainData.push(config);
      }

      function addOption (option, config) {
        config = config || {};