GitLabDropdown.prototype.rowClicked = function()

in app/assets/javascripts/gl_dropdown.js [816:900]
77 lines of code
33 McCabe index (conditional complexity)

  GitLabDropdown.prototype.rowClicked = function(el) {
    var field, groupName, isInput, selectedIndex, selectedObject, value, isMarking;

    const { fieldName } = this.options;
    isInput = $(this.el).is('input');
    if (this.renderedData) {
      groupName = el.data('group');
      if (groupName) {
        selectedIndex = el.data('index');
        selectedObject = this.renderedData[groupName][selectedIndex];
      } else {
        selectedIndex = el.closest('li').index();
        selectedObject = this.renderedData[selectedIndex];
      }
    }

    if (this.options.vue) {
      if (el.hasClass(ACTIVE_CLASS)) {
        el.removeClass(ACTIVE_CLASS);
      } else {
        el.addClass(ACTIVE_CLASS);
      }

      return [selectedObject];
    }

    field = [];
    value = this.options.id ? this.options.id(selectedObject, el) : selectedObject.id;
    if (isInput) {
      field = $(this.el);
    } else if (value != null) {
      field = this.dropdown
        .parent()
        .find(
          "input[name='" + fieldName + "'][value='" + value.toString().replace(/'/g, "\\'") + "']",
        );
    }

    if (this.options.isSelectable && !this.options.isSelectable(selectedObject, el)) {
      return [selectedObject];
    }

    if (el.hasClass(ACTIVE_CLASS) && value !== 0) {
      isMarking = false;
      el.removeClass(ACTIVE_CLASS);
      if (field && field.length) {
        this.clearField(field, isInput);
      }
    } else if (el.hasClass(INDETERMINATE_CLASS)) {
      isMarking = true;
      el.addClass(ACTIVE_CLASS);
      el.removeClass(INDETERMINATE_CLASS);
      if (field && field.length && value == null) {
        this.clearField(field, isInput);
      }
      if ((!field || !field.length) && fieldName) {
        this.addInput(fieldName, value, selectedObject);
      }
    } else {
      isMarking = true;
      if (!this.options.multiSelect || el.hasClass('dropdown-clear-active')) {
        this.dropdown.find('.' + ACTIVE_CLASS).removeClass(ACTIVE_CLASS);
        if (!isInput) {
          this.dropdown
            .parent()
            .find("input[name='" + fieldName + "']")
            .remove();
        }
      }
      if (field && field.length && value == null) {
        this.clearField(field, isInput);
      }
      // Toggle active class for the tick mark
      el.addClass(ACTIVE_CLASS);
      if (value != null) {
        if ((!field || !field.length) && fieldName) {
          this.addInput(fieldName, value, selectedObject);
        } else if (field && field.length) {
          field.val(value).trigger('change');
        }
      }
    }

    return [selectedObject, isMarking];
  };