动态表头 el-table el-dropdown el-checkbox

需求类似下图

1. 样式
   主体是表格 el-table，最后一个表头是按钮，用插槽来实现
   表头字段用下拉菜单实现 el-dropdown
   多选功能用 el-checkbox 来实现

   <template slot="header" slot-scope="scope">
   	<el-dropdown :hide-on-click="false" :index="scope.row">
   		<el-button icon="el-icon-more">el-button>
   		<el-dropdown-menu slot="dropdown">
   			<el-dropdown-item>
   				<el-checkbox :indeterminate="isIndeterminate" v-model="checkAll" @change="handleCheckAllChange">全选el-checkbox>
   			el-dropdown-item>
   			<el-checkbox-group v-model="checkboxs" @change="handleCheckedCitiesChange">
   				<el-dropdown-item v-for="item in headers" :key="item.prop">
   					<el-checkbox :label="item.label" @change="headerChange(item)">{{item.label}}el-checkbox>
   				el-dropdown-item>
   	  		el-checkbox-group>
   		el-dropdown-menu>
   	el-dropdown>
   template>
   

   headers: [
   	{prop:"data",label:"日期",index:"0"},
   	{prop:"name",label:"名字",index:"1"},
   	{prop:"address",label:"地址",index:"2"}
   ], // 总表头数据
   header:[], // 展示的表头
   checkboxs: [], // checkbox-group 数据
   checkAll: false,
   isIndeterminate: true
   

2. 逻辑

   默认全选的状态下，在 mounted 将 headers 数据赋值给 header，将 headers 的 lable 赋值给checkboxs

   resetChecked() {
   	this.checkboxs = []
   	this.header = []
   	this.$nextTick(function () {
   		this.headers.map(item => {
   			this.header.push({
   				prop: item.prop,
   				label: item.label,
   				index: item.index
   			});
   			this.checkboxs.push(item.label);
   		})
   		this.isIndeterminate = false;
   		this.checkAll = true
   	})	
   }
   

   全选和多选请参照 el-checkbox

   	  handleCheckAllChange(val) {
           this.checkedCities = val ? cityOptions : [];
           if (checkedCities.length > 0) {
           	this.resetChecked()
           } else {
           this.checkboxs = []
           this.header = []
           this.isIndeterminate = false;
         },
         handleCheckedCitiesChange(value) {
           let checkedCount = value.length;
           this.checkAll = checkedCount === this.headers.length;
           this.isIndeterminate = checkedCount > 0 && checkedCount < this.headers.length;
         }
   

   表头动态展示+排序

   headerChange(value, index) {
   	let checkedIndex = this.header.findIndex( item => item.prop === value.prop);
   	if (checkedIndex  != -1) {
   		this.header.splice(checkedIndex, 1)
   	} else {
   		this.header.push(value)
   		this.header.sort(this.sortFunc("index"))
   	}
   },
   sortFunc(i) {
   	return funcyion (a,b) {
   		return a[i] - b[i];
   	}
   }
   

3. 注意

   插槽的scope别忘了写