参考文章vue+el-select下拉实现：全选、反选、清空功能

如图，优化代码，支持若依字典

import multipleSelect from '@/components/MultipleSelect/index.vue'

 components: { multipleSelect },


          <el-row>
            <el-form-item label="分管领域" prop="manageDomainArray">
              <multipleSelect v-model="form.manageDomainArray" dictName="tzLyUserDomain"></multipleSelect>
            </el-form-item>
          </el-row>

<template>
  <div>
    <el-select style="width: 100% "
               v-model="selectData"
               size="small"
               multiple
               filterable
               :filter-method="selectDataFilter"
               placeholder="请选择"
               @change="sendMsg()">

      <div class="select_up">
        <el-button type="text" v-on:click="selectAll">
          <i class="el-icon-circle-check"/>
          全选
        </el-button>
        <el-button type="text" v-on:click="selectRemove">
          <i class="el-icon-close"/>
          清空
        </el-button>
        <el-button type="text" v-on:click="selectReverse">
          <i class="el-icon-copy-document"/>
          反选
        </el-button>
      </div>
      <div class="select_list">
        <el-option
          v-for="dict in options"
          :key="dict.dictValue"
          :label="dict.dictLabel"
          :value="dict.dictValue">
        </el-option>
      </div>
    </el-select>

  </div>
</template>
<script>

export default {
  props: {
    //接受父组件v-model数据
    value: {
      type: Array,
      required: [],
      default: function() {
        return []
      }
    },
    dictName: {
      type: String
    }
  },
  watch: {
    //监听父组件v-model数据变化，修改子组件selectData
    value(newValue, oldValue) {
      this.selectData = newValue
    },
    // 监听子组件selectData变化,修改父组件v-model
    selectData: function(newVal, oldVal) {
      this.sendMsg()
    }
  },
  data() {
    return {
      options: [],//下拉选项
      selectData: []//选中数据
    }
  },
  created() {
    this.getDicts(this.dictName).then(res => {
      this.options = res.data
      // 第一次打开,初始化 selectData
      this.selectData = this.value
    })
  },
  methods: {
    //清空操作
    selectRemove() {
      this.selectData = []
    },
    //全选操作
    selectAll() {
      this.options.map(dict => {
        if (!this.selectData.includes(dict.dictValue)) {
          this.selectData.push(dict.dictValue)
        }
      })
    },
    //反选操作
    selectReverse() {
      const val = []
      this.options.forEach(dict => {
        const index = this.selectData.indexOf(dict.dictValue)
        if (index !== -1) {
          // 已选中的项，不加入反选列表
        } else {
          val.push(dict.dictValue)
        }
      })
      this.selectData = val // 直接修改 selectData 数组
    },
    //查询操作
    selectDataFilter(query) {
      if (query !== null && query !== undefined && query.trim() !== '') {
        this.options.forEach(dict => {
          //模糊查询并且不存在
          if (dict.dictLabel.includes(query) && !this.selectData.includes(dict.dictValue)) {
            this.selectData.push(dict.dictValue)
          }
        })
      }
    },
    sendMsg() {
      //input是默认双向绑定事件，select控件也可以用input给父组件传递数据
      this.$emit('input', this.selectData)
    }

  }
}
</script>
<style scoped lang="scss">
.el-select-dropdown__list {
  height: 100%;
  overflow: hidden;

}

.select_up {
  padding: 0 14px;
  font-size: 14px;
  position: absolute;
  z-index: 99999;
  background-color: white;
  top: 0px;
  width: 100%;
  border-radius: 5px 5px 0 0;

  ::v-deep .el-button {
    color: #bcbcbc;
    font-size: 14px;

    i {
      font-size: 14px;
    }
  }

  ::v-deep .el-button:hover {
    color: #409EFF;
  }

  .el-button + .el-button {
    margin-left: 6px;
  }
}

.select_list {
  margin-top: 25px;
}
</style>