EL-FROM动态添加item并设置必填

<el-form ref="form" :model="form" :rules="rules" label-suffix=":" label-width="110px"
             label-position="center" size="mini">
    <el-button  @click="add" type="primary">添加</el-button>
    <div v-for="(item,index) in form.arr" :key="index">
        <el-form-item label="部门" label-width="60px"  :prop="'arr.'+index+'.dept'" :rules="rules.dept">
          <el-input v-model="item.dept"  />
        </el-form-item>
        <el-form-item label="姓名" :prop="'arr.'+index+'.userName'"                 
                   :rules="rules.userName">
        <el-input v-model="item.userName"  />
        </el-form-item>
        <el-form-item label="工号" :prop="'arr.'+index+'.userNumber'" :rules="rules.userNumber">
         <el-input v-model="item.userNumber"  />
        </el-form-item>
     </div>
 </el-form>

rules: {
         edpt:[{required: true, message: "请输入部门", trigger: "blur"}],
         UserName:[{ required: true, message: "请输入姓名", trigger: "blur"}],
         UserNumber:[{ required: true, message: "请输入工号", trigger: "blur"}],
 }

效果