ElementUI中el-radio再次点击取消选中

方法：

<el-radio-group v-model="isContain" >
    <el-radio @click.native.prevent="checkClick(1)" :label="1">包含</el-radio>
    <el-radio @click.native.prevent="checkClick(0)" :label="0">不包含</el-radio>
</el-radio-group>

checkClick (e) {
   e === this.isContain ? this.isContain = '' : this.isContain = e;
},