41. 购物车 - 封装 getters - 动态计算展示

1. 封装 getters：商品总数 / 选中的商品列表 / 选中的商品总数 / 选中的商品总价

getters: {
  cartTotal (state) {
    return state.cartList.reduce((sum, item, index) => sum + item.goods_num, 0)
  },
  selCartList (state) {
    return state.cartList.filter(item => item.isChecked)
  },
  selCount (state, getters) {
    return getters.selCartList.reduce((sum, item, index) => sum + item.goods_num, 0)
  },
  selPrice (state, getters) {
    return getters.selCartList.reduce((sum, item, index) => {
      return sum + item.goods_num * item.goods.goods_price_min
    }, 0).toFixed(2)
  }
}

[](data:image/svg+xml;base64,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)

1. 页面中 mapGetters 映射使用

computed: {
  ...mapGetters('cart', ['cartTotal', 'selCount', 'selPrice']),
},

<!-- 购物车开头 -->
<div class="cart-title">
  <span class="all">共<i>{{ cartTotal || 0 }}</i>件商品</span>
  <span class="edit">
    <van-icon name="edit"  />
    编辑
  </span>
</div>

<div class="footer-fixed">
  <div  class="all-check">
    <van-checkbox  icon-size="18"></van-checkbox>
    全选
  </div>
  <div class="all-total">
    <div class="price">
      <span>合计：</span>
      <span>¥ <i class="totalPrice">{{ selPrice }}</i></span>
    </div>
    <div v-if="true" :class="{ disabled: selCount === 0 }" class="goPay">
      结算({{ selCount }})
    </div>
    <div v-else  :class="{ disabled: selCount === 0 }" class="delete">
      删除({{ selCount }})
    </div>
  </div>
</div>

[](data:image/svg+xml;base64,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)

42. 购物车 - 全选反选功能

1. 全选 getters

getters: {
  isAllChecked (state) {
    return state.cartList.every(item => item.isChecked)
  }
}

...mapGetters('cart', ['isAllChecked']),

<div class="all-check">
  <van-checkbox :value="isAllChecked" icon-size="18"></van-checkbox>
  全选
</div>

[](data:image/svg+xml;base64,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)

1. 点击小选，修改状态

<van-checkbox @click="toggleCheck(item.goods_id)" ...></van-checkbox>

toggleCheck (goodsId) {
  this.$store.commit('cart/toggleCheck', goodsId)
},

mutations: {
  toggleCheck (state, goodsId) {
    const goods = state.cartList.find(item => item.goods_id === goodsId)
    goods.isChecked = !goods.isChecked
  },
}

[](data:image/svg+xml;base64,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)

1. 点击全选，重置状态