【study】全选，单独勾选的逻辑思路

一.全选，单独勾选的逻辑思路

1. 首先要判断点击的是全选，还是其中的单独每一项
2. 如果第一次点的是全选，那么单独的每一项就需要全部选中，如果第二次还是点击全选呢？这时就需要判断一下，如果再次点击全选，即是全不选的思路，即全选取反
3. 如果点击的是单独的每一项，直接取反即可，但是有一种情况就是，所有的单独选项都被勾选，那么全选是不是就需要被勾选呢？如果此时在有一项甚至几项取消，那么不符合全选，此时的全选也应该随着取消

//html
<template>
  <div class="box">
    <div class="all">
      <div v-for="(data, index) in datalist" :key="index" @click="handleClick(index)">
        <p class="data">
          <span class="data_text">{{ data.text }}</span>
          <span v-if="data.isSelect" class="data_icon"><i class="el-icon-check"></i></span>
        </p>
      </div>
    </div>
    <!-- 点击确定按钮，勾选什么内容，这里显示什么内容 -->
    <button @click=handleSure>确定</button>
    <div class="contentText">{{ contentText }}</div>
  </div>
</template>

//js
<script>
export default {
  data() {
    return {
      datalist: [
        { text: "全部", isSelect: false },
        { text: "李钟硕", isSelect: false },
        { text: "蔡徐坤", isSelect: false },
        { text: "朱正廷", isSelect: false },
        { text: "范丞丞", isSelect: false },
        { text: "黄明昊", isSelect: false },
      ],
      contentText: "李钟硕",
    };
  },
  methods: {
    handleClick(index) {
      if (index === 0) {
        //第一次点击全部选中
        let firstSelect = this.datalist[0].isSelect;
        this.datalist.forEach((item) => {
          if (firstSelect) {
            item.isSelect = false;
          } else {
            item.isSelect = true;
          }
        });
      } else {
        //点击每一项
        this.datalist[index].isSelect = !this.datalist[index].isSelect;
        let AllSelect = this.datalist.slice(1).every((item) => {
          return item.isSelect;
        });
        this.datalist[0].isSelect = AllSelect;
      }
    },
    handleSure () {
      let content = ''
      this.datalist.slice(1).forEach((item) => {
          if(item.isSelect === true) {
              content += item.text +','
              this.contentText = content
          }
      })
    }
  },
};
</script>

//css
<style lang="scss">
.box {
  width: 100%;
  .all {
    width: 400px;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    .data {
      border: 1px solid pink;
      width: 100px;
      height: 40px;
      line-height: 40px;
      display: flex;
      justify-content: space-between;
      padding: 0px 5px;
    }
  }
  button {
    width: 100px;
    height: 40px;
    line-height: 40px;
    margin-bottom: 20px;
  }
  .contentText {
    font-size: 22px;
  }
}
</style>