framework/js/lib/helpers/listItems.js

import Separator from 'flarum/components/Separator';

function isSeparator(item) {
  return item && item.component === Separator;
}

function withoutUnnecessarySeparators(items) {
  const newItems = [];
  let prevItem;

  items.forEach((item, i) => {
    if (!isSeparator(item) || (prevItem && !isSeparator(prevItem) && i !== items.length - 1)) {
      prevItem = item;
      newItems.push(item);
    }
  });

  return newItems;
}

/**
 * The `listItems` helper wraps a collection of components in <li> tags,
 * stripping out any unnecessary `Separator` components.
 *
 * @param {Array} items
 * @return {Array}
 */
export default function listItems(items) {
  return withoutUnnecessarySeparators(items).map(item => {
    const isListItem = item.component && item.component.isListItem;
    const className = item.props ? item.props.itemClassName : item.itemClassName;

    return isListItem
      ? item
      : <li className={(item.itemName ? 'item-' + item.itemName : '') + ' ' + (className || '')}>{item}</li>;
  });
};