dedup.ts

export const dedupItems = (
  items: DumplingItem[]
): [DumplingItem[], DumplingItem[]] => {
  let dupeItems = [];
  let newItems = [];
  for (const item of items) {
    let i = newItems.findIndex(({ sellerId }) => sellerId === item.sellerId);
    if (i !== -1) {
      dupeItems.push(item);
      newItems[i].categories.push(...item.categories);
      newItems[i].categories = _.uniq(newItems[i].categories);
    } else {
      newItems.push(item);
    }
  }
  return [newItems, dupeItems];
};