认识SKU组件

SKU组件的作用

产出当前用户选择的商品规格，为加入购物车操作提供数据信息，在选择的过程中，组件的选中状态要进行更新，组件还要提示用户当前规格是否禁用，每次选择都要产出对应的sku数据

SKU组件的使用
假如你在开发的过程中要使用别人开发好的组件，重点看什么？
props和emit，props决定了当前组件接收什么数据，emit决定了会产出什么数据

点击规格

准备模版渲染规格数据

<script setup>
import { onMounted, ref } from 'vue'
import axios from 'axios'
// 商品数据
const goods = ref({})
const getGoods = async () => {
  // 1135076  初始化就有无库存的规格
  // 1369155859933827074 更新之后有无库存项（蓝色-20cm-中国）
  const res = await axios.get('http://pcapi-xiaotuxian-front-devtest.itheima.net/goods?id=1369155859933827074')
  goods.value = res.data.result
}
onMounted(() => getGoods())

</script>

<template>
  <div class="goods-sku">
    <dl v-for="item in goods.specs" :key="item.id">
      <dt>{{ item.name }}</dt>
      <dd>
        <template v-for="val in item.values" :key="val.name">
          <!-- 图片类型规格 -->
          <img v-if="val.picture" :src="val.picture" :title="val.name">
          <!-- 文字类型规格 -->
          <span v-else>{{ val.name }}</span>
        </template>
      </dd>
    </dl>
  </div>
</template>

<style scoped lang="scss">
@mixin sku-state-mixin {
  border: 1px solid #e4e4e4;
  margin-right: 10px;
  cursor: pointer;

  &.selected {
    border-color: #27ba9b;
  }

  &.disabled {
    opacity: 0.6;
    border-style: dashed;
    cursor: not-allowed;
  }
}

.goods-sku {
  padding-left: 10px;
  padding-top: 20px;

  dl {
    display: flex;
    padding-bottom: 20px;
    align-items: center;

    dt {
      width: 50px;
      color: #999;
    }

    dd {
      flex: 1;
      color: #666;

      >img {
        width: 50px;
        height: 50px;
        margin-bottom: 4px;
        @include sku-state-mixin;
      }

      >span {
        display: inline-block;
        height: 30px;
        line-height: 28px;
        padding: 0 20px;
        margin-bottom: 4px;
        @include sku-state-mixin;
      }
    }
  }
}
</style>

选中和取消选中实现

基本思路：

1. 每一个规格按钮都拥有自己的选中状态数据-selected，true为选中，false为取消选中
2. 配合动态class，把选中状态selected作为判断条件，true让active类名显示，false让active类名不显示
3. 点击的是未选中，把同一个规格的其他取消选中，当前点击项选中；点击的是已选中，直接取消

<script setup>
// 省略代码
// 选中和取消选中实现
const changeSku = (item, val) => {
  // 点击的是未选中，把同一个规格的其他取消选中，当前点击项选中，点击的是已选中，直接取消
  if (val.selected) {
    val.selected = false
  } else {
    item.values.forEach(valItem => valItem.selected = false)
    val.selected = true
  }
}
</script>

<template>
  <div class="goods-sku">
    <dl v-for="item in goods.specs" :key="item.id">
      <dt>{{ item.name }}</dt>
      <dd>
        <template v-for="val in item.values" :key="val.name">
          <img v-if="val.picture" 
            @click="changeSku(item, val)" 
            :class="{ selected: val.selected }" 
            :src="val.picture"
            :title="val.name">
          <span v-else 
            @click="changeSku(val)" 
            :class="{ selected: val.selected }">{{ val.name }}</span>
        </template>
      </dd>
    </dl>
  </div>
</template>

点击规格更新禁用状态—生成有效路径字典

规格禁用判断的依据是什么？
核心原理：当前的规格sku，或者组合起来的规格sku，在skus数组中对应的库存为0时，当前规格会被禁用，生成路径字典是为了协助和简化这个匹配过程

实现步骤
1️⃣根据库存字段得到有效的sku数组
2️⃣根据有效的sku数组使用powerSet算法得到所有子集
3️⃣根据子集生成路径字典对象
生成有效路径字典对象

import powerSet from './power-set'
const getPathMap = (goods) => {
  const pathMap = {}
  // 1. 得到所有有效的Sku集合 
  const effectiveSkus = goods.skus.filter(sku => sku.inventory > 0)
  
  // 2. 根据有效的Sku集合使用powerSet算法得到所有子集 [1,2] => [[1], [2], [1,2]]
  effectiveSkus.forEach(sku => {
    // 2.1 获取匹配的valueName组成的数组
    const selectedValArr = sku.specs.map(val => val.valueName)
    // 2.2 使用算法获取子集
    const valueArrPowerSet = powerSet(selectedValArr)
    // 3. 根据子集生成最终的路径字典对象
    // 3.1 遍历子集 往pathMap中插入数据
    valueArrPowerSet.forEach(arr => {
      // 根据Arr得到字符串的key，约定使用-分割 ['蓝色'，'美国'] => '蓝色-美国'
      //初始化key 数组join -> 字符串  对象的key
      const key = arr.join('-')
      //如果已经存在当前key了 就往数组中直接添加skuId 如果不存在key 直接做赋值 
      if (pathMap[key]) {
        pathMap[key].push(sku.id)
      } else {
        pathMap[key] = [sku.id]
      }
    })
  })
  return pathMap
}
// 数据获取完毕生成路径字典
let pathMap = {}
const getGoods = async () => {
  // 1135076  初始化就有无库存的规格
  // 1369155859933827074 更新之后有无库存项（蓝色-20cm-中国）
  const res = await axios.get('http://pcapi-xiaotuxian-front-devtest.itheima.net/goods?id=1135076')
  goods.value = res.data.result
  pathMap = getPathMap(goods.value)
  // 初始化更新按钮状态
  initDisabledState(goods.value.specs, pathMap)
}

power-set.js

export default function bwPowerSet (originalSet) {
  const subSets = []

  // We will have 2^n possible combinations (where n is a length of original set).
  // It is because for every element of original set we will decide whether to include
  // it or not (2 options for each set element).
  const numberOfCombinations = 2 ** originalSet.length

  // Each number in binary representation in a range from 0 to 2^n does exactly what we need:
  // it shows by its bits (0 or 1) whether to include related element from the set or not.
  // For example, for the set {1, 2, 3} the binary number of 0b010 would mean that we need to
  // include only "2" to the current set.
  for (let combinationIndex = 0; combinationIndex < numberOfCombinations; combinationIndex += 1) {
    const subSet = []

    for (let setElementIndex = 0; setElementIndex < originalSet.length; setElementIndex += 1) {
      // Decide whether we need to include current element into the subset or not.
      if (combinationIndex & (1 << setElementIndex)) {
        subSet.push(originalSet[setElementIndex])
      }
    }

    // Add current subset to the list of all subsets.
    subSets.push(subSet)
  }
  return subSets
}

点击规格更新禁用状态—初始化规格禁用

思路：遍历每一个规格对象，使用nam字段作为key去路径字典pathMap中做匹配，匹配不上则禁用
怎么做到显示上的禁用呢？
1️⃣通过增加disabled字段，匹配上路径字段，disabled为false，匹配不上路径字段，disabled为true
2️⃣配合动态类名控制禁用类名

// 1. 定义初始化函数
// specs：商品源数据 pathMap：路径字典
const initDisabledState = (specs, pathMap) => {
  // 约定：每一个按钮的状态由自身的disabled进行控制
  specs.forEach(item => {
    item.values.forEach(val => {
      // 路径字典中查找是否有数据 有-可以点击 没有-禁用
      val.disabled = !pathMap[val.name]
    })
  })
}

// 2. 在数据返回后进行初始化处理
let patchMap = {}
const getGoods = async () => {
  // 1135076  初始化就有无库存的规格
  // 1369155859933827074 更新之后有无库存项（蓝色-20cm-中国）
  const res = await axios.get('http://pcapi-xiaotuxian-front-devtest.itheima.net/goods?id=1135076')
  goods.value = res.data.result
  pathMap = getPathMap(goods.value)
  // 初始化更新按钮状态
  initDisabledState(goods.value.specs, pathMap)
}

点击规格更新禁用状态—点击时组合禁用更新

思路（点击规格时）
1️⃣按照顺序得到规格选项中的数组[‘蓝色’,‘20cm’,‘undefined’]
2️⃣遍历每一个规格
把name字段的值填充到对应的位置
过滤掉undefined项使用join方法形成一个有效的key
使用key去pathMap中进行匹配，匹配不删，则当前项禁用

结合上面图片，蓝色-20cm-中国 在数组中是没有的，所以中国应该禁用掉

// 获取选中项的匹配数组
const getSelectedArr = (specs) => {
  const selectedArr = []
  specs.forEach((spec, index) => {
  //目标：找到valus中selected为true的项，然后把它的name字段添加数组对应的位置
    const selectedVal = spec.values.find(val => val.selected)
    if (selectedVal) {
      selectedArr[index] = selectedVal.name
    } else {
      selectedArr[index] = undefined
    }
  })
  return selectedArr
}
// 更新按钮的禁用状态
const updateDisabledStatus = (specs, pathMap) => {
  // 遍历每一种规格
  specs.forEach((item, i) => {
    // 拿到当前选择的项目
    const selectedArr = getSelectedArr(specs)
    // 遍历每一个按钮
    item.values.forEach(val => {
      if (!val.selected) {
        selectedArr[i] = val.name
        // 去掉undefined之后组合成key
        const key = selectedArr.filter(value => value).join(spliter)
        val.disabled = !pathMap[key]
      }
    })
  })
}

产出有效的SKU信息

什么是有效的SKU？
颜色 尺寸 产地都选择了

如何判断当前用户已经选择了所有有效的规格？
已选择项数组[‘蓝色’,‘20cm’,‘undefined’]中找不到undefined，那么用户已经选择了所有的有效规格，此时可以产出数据

如何获取当前SKU信息对象？
把已选择项数组拼接为路径字典的key，去路径字典pathMap中找即可

//产出SKU对象数据
const index = getSelectedArr(goods.value.specs).findIndex(item=>item === undefined)
if(index>-1){
 console.log('找到了，信息不完整')
 }else{
 console.log('没找到了，信息完整，可以产出')
 //获取SKU对象
 getSelectedArr(goods.value.specs).join('*')
 const skuIds = pathMap[key]
 console.log('sku对象',skuIds)
 //以skuIds作为匹配项去goods.value.skus数组中找
 }

完整代码

Xtxsku/index.vue

<template>
  <div class="goods-sku">
    <dl v-for="item in goods.specs" :key="item.id">
      <dt>{{ item.name }}</dt>
      <dd>
        <template v-for="val in item.values" :key="val.name">
          <img :class="{ selected: val.selected, disabled: val.disabled }" @click="clickSpecs(item, val)"
            v-if="val.picture" :src="val.picture" />
          <span :class="{ selected: val.selected, disabled: val.disabled }" @click="clickSpecs(item, val)" v-else>{{
              val.name
          }}</span>
        </template>
      </dd>
    </dl>
  </div>
</template>
<script>
import { watchEffect } from 'vue'
import getPowerSet from './power-set'
const spliter = '★'
// 根据skus数据得到路径字典对象
const getPathMap = (skus) => {
  const pathMap = {}
  if (skus && skus.length > 0) {
    skus.forEach(sku => {
      // 1. 过滤出有库存有效的sku
      if (sku.inventory) {
        // 2. 得到sku属性值数组
        const specs = sku.specs.map(spec => spec.valueName)
        // 3. 得到sku属性值数组的子集
        const powerSet = getPowerSet(specs)
        // 4. 设置给路径字典对象
        powerSet.forEach(set => {
          const key = set.join(spliter)
          // 如果没有就先初始化一个空数组
          if (!pathMap[key]) {
            pathMap[key] = []
          }
          pathMap[key].push(sku.id)
        })
      }
    })
  }
  return pathMap
}

// 初始化禁用状态
function initDisabledStatus (specs, pathMap) {
  if (specs && specs.length > 0) {
    specs.forEach(spec => {
      spec.values.forEach(val => {
        // 设置禁用状态
        val.disabled = !pathMap[val.name]
      })
    })
  }
}

// 得到当前选中规格集合
const getSelectedArr = (specs) => {
  const selectedArr = []
  specs.forEach((spec, index) => {
    const selectedVal = spec.values.find(val => val.selected)
    if (selectedVal) {
      selectedArr[index] = selectedVal.name
    } else {
      selectedArr[index] = undefined
    }
  })
  return selectedArr
}

// 更新按钮的禁用状态
const updateDisabledStatus = (specs, pathMap) => {
  // 遍历每一种规格
  specs.forEach((item, i) => {
    // 拿到当前选择的项目
    const selectedArr = getSelectedArr(specs)
    // 遍历每一个按钮
    item.values.forEach(val => {
      if (!val.selected) {
        selectedArr[i] = val.name
        // 去掉undefined之后组合成key
        const key = selectedArr.filter(value => value).join(spliter)
        val.disabled = !pathMap[key]
      }
    })
  })
}


export default {
  name: 'XtxGoodSku',
  props: {
    // specs:所有的规格信息  skus:所有的sku组合
    goods: {
      type: Object,
      default: () => ({ specs: [], skus: [] })
    }
  },
  emits: ['change'],
  setup (props, { emit }) {
    let pathMap = {}
    watchEffect(() => {
      // 得到所有字典集合
      pathMap = getPathMap(props.goods.skus)
      // 组件初始化的时候更新禁用状态
      initDisabledStatus(props.goods.specs, pathMap)
    })

    const clickSpecs = (item, val) => {
      if (val.disabled) return false
      // 选中与取消选中逻辑
      if (val.selected) {
        val.selected = false
      } else {
        item.values.forEach(bv => { bv.selected = false })
        val.selected = true
      }
      // 点击之后再次更新选中状态
      updateDisabledStatus(props.goods.specs, pathMap)
      // 把选择的sku信息传出去给父组件
      // 触发change事件将sku数据传递出去
      const selectedArr = getSelectedArr(props.goods.specs).filter(value => value)
      // 如果选中得规格数量和传入得规格总数相等则传出完整信息(都选择了)
      // 否则传出空对象
      if (selectedArr.length === props.goods.specs.length) {
        // 从路径字典中得到skuId
        const skuId = pathMap[selectedArr.join(spliter)][0]
        const sku = props.goods.skus.find(sku => sku.id === skuId)
        // 传递数据给父组件
        emit('change', {
          skuId: sku.id,
          price: sku.price,
          oldPrice: sku.oldPrice,
          inventory: sku.inventory,
          specsText: sku.specs.reduce((p, n) => `${p} ${n.name}：${n.valueName}`, '').trim()
        })
      } else {
        emit('change', {})
      }
    }
    return { clickSpecs }
  }
}
</script>

<style scoped lang="scss">
@mixin sku-state-mixin {
  border: 1px solid #e4e4e4;
  margin-right: 10px;
  cursor: pointer;

  &.selected {
    border-color: $xtxColor;
  }

  &.disabled {
    opacity: 0.6;
    border-style: dashed;
    cursor: not-allowed;
  }
}

.goods-sku {
  padding-left: 10px;
  padding-top: 20px;

  dl {
    display: flex;
    padding-bottom: 20px;
    align-items: center;

    dt {
      width: 50px;
      color: #999;
    }

    dd {
      flex: 1;
      color: #666;

      >img {
        width: 50px;
        height: 50px;
        margin-bottom: 4px;
        @include sku-state-mixin;
      }

      >span {
        display: inline-block;
        height: 30px;
        line-height: 28px;
        padding: 0 20px;
        margin-bottom: 4px;
        @include sku-state-mixin;
      }
    }
  }
}
</style>

Xtxsku/power-set.js

export default function bwPowerSet (originalSet) {
  const subSets = []

  // We will have 2^n possible combinations (where n is a length of original set).
  // It is because for every element of original set we will decide whether to include
  // it or not (2 options for each set element).
  const numberOfCombinations = 2 ** originalSet.length

  // Each number in binary representation in a range from 0 to 2^n does exactly what we need:
  // it shows by its bits (0 or 1) whether to include related element from the set or not.
  // For example, for the set {1, 2, 3} the binary number of 0b010 would mean that we need to
  // include only "2" to the current set.
  for (let combinationIndex = 0; combinationIndex < numberOfCombinations; combinationIndex += 1) {
    const subSet = []

    for (let setElementIndex = 0; setElementIndex < originalSet.length; setElementIndex += 1) {
      // Decide whether we need to include current element into the subset or not.
      if (combinationIndex & (1 << setElementIndex)) {
        subSet.push(originalSet[setElementIndex])
      }
    }

    // Add current subset to the list of all subsets.
    subSets.push(subSet)
  }

  return subSets
}

页面使用

<script setup>
import { onMounted, ref } from 'vue'
import { useRoute } from 'vue-router'
const goods = ref({})
const route = useRoute()
const getGoods = async () => {
  const res = await getDetail(route.params.id)
  goods.value = res.result
}
onMounted(() => getGoods())
// sku规格被操作时
let skuObj = {}
const skuChange = (sku) => {
  console.log(sku)
  skuObj = sku
}
</script>
  <!-- sku组件 -->
  <XtxSku :goods="goods" @change="skuChange" />