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复杂的官方文档

大家好，编写elementUI时，看到新的element-plus的表单验证部分写的如此的复杂，我下面复制官方文档的表单验证部分的代码。

<template>
  <el-form
    ref="ruleFormRef"
    :model="ruleForm"
    :rules="rules"
    label-width="120px"
    class="demo-ruleForm"
    :size="formSize"
  >
    <el-form-item label="Activity name" prop="name">
      <el-input v-model="ruleForm.name" />
    </el-form-item>
    <el-form-item label="Activity zone" prop="region">
      <el-select v-model="ruleForm.region" placeholder="Activity zone">
        <el-option label="Zone one" value="shanghai" />
        <el-option label="Zone two" value="beijing" />
      </el-select>
    </el-form-item>
    <el-form-item label="Activity time" required>
      <el-col :span="11">
        <el-form-item prop="date1">
          <el-date-picker
            v-model="ruleForm.date1"
            type="date"
            placeholder="Pick a date"
            style="width: 100%"
          />
        </el-form-item>
      </el-col>
      <el-col class="text-center" :span="2">
        <span class="text-gray-500">-</span>
      </el-col>
      <el-col :span="11">
        <el-form-item prop="date2">
          <el-time-picker
            v-model="ruleForm.date2"
            placeholder="Pick a time"
            style="width: 100%"
          />
        </el-form-item>
      </el-col>
    </el-form-item>
    <el-form-item label="Instant delivery" prop="delivery">
      <el-switch v-model="ruleForm.delivery" />
    </el-form-item>
    <el-form-item label="Activity type" prop="type">
      <el-checkbox-group v-model="ruleForm.type">
        <el-checkbox label="Online activities" name="type" />
        <el-checkbox label="Promotion activities" name="type" />
        <el-checkbox label="Offline activities" name="type" />
        <el-checkbox label="Simple brand exposure" name="type" />
      </el-checkbox-group>
    </el-form-item>
    <el-form-item label="Resources" prop="resource">
      <el-radio-group v-model="ruleForm.resource">
        <el-radio label="Sponsorship" />
        <el-radio label="Venue" />
      </el-radio-group>
    </el-form-item>
    <el-form-item label="Activity form" prop="desc">
      <el-input v-model="ruleForm.desc" type="textarea" />
    </el-form-item>
    <el-form-item>
      <el-button type="primary" @click="submitForm(ruleFormRef)"
        >Create</el-button
      >
      <el-button @click="resetForm(ruleFormRef)">Reset</el-button>
    </el-form-item>
  </el-form>
</template>

<script lang="ts" setup>
import { reactive, ref } from 'vue'
import type { FormInstance, FormRules } from 'element-plus'

const formSize = ref('default')
const ruleFormRef = ref<FormInstance>()
const ruleForm = reactive({
  name: 'Hello',
  region: '',
  date1: '',
  date2: '',
  delivery: false,
  type: [],
  resource: '',
  desc: '',
})

const rules = reactive<FormRules>({
  name: [
    { required: true, message: 'Please input Activity name', trigger: 'blur' },
    { min: 3, max: 5, message: 'Length should be 3 to 5', trigger: 'blur' },
  ],
  region: [
    {
      required: true,
      message: 'Please select Activity zone',
      trigger: 'change',
    },
  ],
  date1: [
    {
      type: 'date',
      required: true,
      message: 'Please pick a date',
      trigger: 'change',
    },
  ],
  date2: [
    {
      type: 'date',
      required: true,
      message: 'Please pick a time',
      trigger: 'change',
    },
  ],
  type: [
    {
      type: 'array',
      required: true,
      message: 'Please select at least one activity type',
      trigger: 'change',
    },
  ],
  resource: [
    {
      required: true,
      message: 'Please select activity resource',
      trigger: 'change',
    },
  ],
  desc: [
    { required: true, message: 'Please input activity form', trigger: 'blur' },
  ],
})

const submitForm = async (formEl: FormInstance | undefined) => {
  if (!formEl) return
  await formEl.validate((valid, fields) => {
    if (valid) {
      console.log('submit!')
    } else {
      console.log('error submit!', fields)
    }
  })
}

const resetForm = (formEl: FormInstance | undefined) => {
  if (!formEl) return
  formEl.resetFields()
}
</script>

一个简单的表单验证写的这么啰嗦，我就想校验一下登录账号和密码，需要这么麻烦吗？

其实只需要FormInstance就可以实现了。

超简单的写法

对于简单的表单验证，完全不需要上面那么啰嗦。

其实验证是很简单的，只需要写一个验证的数组(rules)，并赋值给el-form组件的rule参数即可，如下

<el-form ref="formRef" :model="loginForm" :rules="rules" label-position="top"></el-form>

rules长这样

const rules = ref({
      phone: [
        {required: true, message: '必须输入手机号码', trigger: 'blur'},
        {pattern: /^1[3456789]\d{9}$/, message: '手机号码格式不正确', trigger: 'blur'},
      ],
      password: [
        {required: true, message: '必须输入密码', trigger: 'blur'},
        {min: 6, max: 20, message: '密码长度在 6 到 20 个字符', trigger: 'blur'},
      ]
    })

那你可能会问了，ref是干啥用的啊？

告诉你，ref的目的是为了在提交或者什么操作的时候，手动验证表单，如下。

比如我们有个登录按钮，和登录的方法onLogin()

<el-button type="primary" @click="onLogin(formRef)">登录</el-button>

const onLogin = (form) => {
      form.validate((valid, fields) => {
        if (valid) {
          console.log('登录成功')
        } else {
          console.log('error submit!', fields)
        }
      })
    }

相信小伙伴们已经看明白什么意思了。

简单来说，就是在登录方法里传参传这个ref进去，然后这个ref有validate()方法，通过这个方法就校验了。上面的if else是固定写法。

那么ref这个值是哪来的呢？其实是开头说的FormInstance定义出来的，定义如下：

// 引用
import {FormInstance} from "element-plus"

// 这个是写在setup()里的！！
const formRef = ref<FormInstance>('')

怎么样，是不是比官方那啰里啰嗦一大串舒服多了？