把 cartList[shopId]?.[item._id]?.[‘count’] 改成item.count 能获取到count，打印list也是有count属性。但是不明白list是通过getContentData方法获取到的，为什么会有count属性?

//html
<div class="product__item__num">
            <span class="product__num__minus" @click="changeCartItemInfo(shopId, item._id, item, -1)">-</span>
            <span class="product__num__text">{{cartList[shopId]?.[item._id]?.['count'] || 0}}</span>
            <span class="product__num__plus" @click="changeCartItemInfo(shopId, item._id, item, 1)">+</span>
</div>

//js
const useCurrentListEffect = (currentTab, shopId) => {
  const content = reactive({ list: [] })
  const getContentData = async () => {
    const result = await get(`/api/shop/${shopId}/products`, { tab: currentTab.value })
    if (result?.errno === 0) {
      content.list = result.data
    }
  }
  watchEffect(() => { getContentData() })
  const { list } = toRefs(content)
  return { list }
}