重置后出现Vuetify表单验证错误

Question

我在一个组件中有以下内容：

<v-form v-model="valid" ref="form" class="px-3">
  <v-text-field label="First Name" v-model="firstname" :rules="inputRules"></v-text-field>
  <v-text-field label="Last Name" v-model="lastname" :rules="inputRules"></v-text-field>
  <v-text-field label="Email" v-model="email"></v-text-field>
  <v-btn :loading="loading" flat class="success mx-0 mt-3" @click="submit">Create Person</v-btn>
</v-form>

脚本：

export default {
  data() {
    return {
      valid: true,
      firstname: '',
      lastname: '',
      email: '',
      loading: false,
      dialog: false,
      inputRules: [
        v => v.length >= 2 || 'Minimum length is 2 characters'
      ]
    }
  },
  methods: {
    submit() {
      if(this.$refs.form.validate()) {
        this.loading = true;

        const person = {
          firstname: this.firstname,
          lastname: this.lastname,
          email: this.email
        };

        sendToMyDB(person).then(()=>{
          this.loading = false;
          this.dialog = false;
          this.$refs.form.reset();
        })
      }
    }
  }
}

因此，我将表单数据提交到我的数据库，然后在成功promise中，我使用它。$refs.form.reset（）；重新设置我的表单。

但是，我会立即收到错误消息，并且在每次提交后都会收到错误消息：

"[Vue警告]：错误在下一个滴答："TypeError：无法读取属性'长度'的未定义"

和

TypeError:无法读取未定义的属性“length”

Answer 1

Vuetify正在将未定义的传递给在inpuput规则中引用的函数。您可以看到它正在读取堆栈调用：

我建议您在访问其内容之前测试v是否未定义：

v => (v && v.length >= 2) || 'Minimum length is 2 characters' 

或者

v => (!v || v.length >= 2) || 'Minimum length is 2 characters'

取决于您的业务规则。

var app = new Vue({
  el: '#app',
  data() {
    return {
      valid: true,
      firstname: '',
      lastname: '',
      email: '',
      loading: false,
      dialog: false,
      inputRules: [
        v => (v && v.length >= 2) || 'Minimum length is 2 characters'
      ]
    }
  },
  methods: {
    submit() {
      if (this.$refs.form.validate()) {
        this.loading = true;

        const person = {
          firstname: this.firstname,
          lastname: this.lastname,
          email: this.email
        };

        /* sendToMyDB(person) */
        Promise.resolve().then(() => {
          this.loading = false;
          this.dialog = false;
          this.$refs.form.reset();
        })
      }
    }
  }
});

<script src="https://unpkg.com/vue/dist/vue.min.js"></script>
<script src="https://unpkg.com/vuetify/dist/vuetify.min.js"></script>

<div id="app">
  <v-form v-model="valid" ref="form" class="px-3">
    <v-text-field label="First Name" v-model="firstname" :rules="inputRules"></v-text-field>
    <v-text-field label="Last Name" v-model="lastname" :rules="inputRules"></v-text-field>
    <v-text-field label="Email" v-model="email"></v-text-field>
    <v-btn :loading="loading" text class="success mx-0 mt-3" @click="submit">Create Person</v-btn>
  </v-form>
</div>