elementUI 表单验证：获取到input中的值(value)，显示undefined

<el-form ref="dataForm" :rules="rules" :model="dataForm" label-width="100px">
    <el-form-item label="年龄" prop="infoList.age">
    <el-input v-model="dataForm.infoList.age" type="text" />
    </el-form-item>
 </el-form>
<script>
  export default {
    data() {
      const valiNonnegative = (rule, value, callback) => { // 非负数
      const reg = /^[+]{0,1}(\d+)$|^[+]{0,1}(\d+\.\d+)$/
      if (!reg.test(value)) {
        callback(new Error('请输入非负数'))
      } else {
        callback()
      }
    };
      return {
        dataForm: {
          infoList: {
             age:''
            }
        },
        rules: {
          'infoList.age': { validator: valiNonnegative , trigger: 'blur' }
        }
      };
    }

原本出错的地方 如下： 

参考：vue-element Form表单验证踩坑（表单验证明明有值，却提示错误)