4dkankan-components/docs/examples/form/custom-validation.vue

<template>
    <el-form ref="ruleFormRef" :model="ruleForm" status-icon :rules="rules" label-width="120px" class="demo-ruleForm">
        <el-form-item label="Password" prop="pass">
            <el-input v-model="ruleForm.pass" type="password" autocomplete="off" />
        </el-form-item>
        <el-form-item label="Confirm" prop="checkPass">
            <el-input v-model="ruleForm.checkPass" type="password" autocomplete="off" />
        </el-form-item>
        <el-form-item label="Age" prop="age">
            <el-input v-model.number="ruleForm.age" />
        </el-form-item>
        <el-form-item>
            <el-button type="primary" @click="submitForm(ruleFormRef)">Submit</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 } from 'element-plus'

const ruleFormRef = ref<FormInstance>()

const checkAge = (rule: any, value: any, callback: any) => {
    if (!value) {
        return callback(new Error('Please input the age'))
    }
    setTimeout(() => {
        if (!Number.isInteger(value)) {
            callback(new Error('Please input digits'))
        } else {
            if (value < 18) {
                callback(new Error('Age must be greater than 18'))
            } else {
                callback()
            }
        }
    }, 1000)
}

const validatePass = (rule: any, value: any, callback: any) => {
    if (value === '') {
        callback(new Error('Please input the password'))
    } else {
        if (ruleForm.checkPass !== '') {
            if (!ruleFormRef.value) return
            ruleFormRef.value.validateField('checkPass', () => null)
        }
        callback()
    }
}
const validatePass2 = (rule: any, value: any, callback: any) => {
    if (value === '') {
        callback(new Error('Please input the password again'))
    } else if (value !== ruleForm.pass) {
        callback(new Error("Two inputs don't match!"))
    } else {
        callback()
    }
}

const ruleForm = reactive({
    pass: '',
    checkPass: '',
    age: '',
})

const rules = reactive({
    pass: [{ validator: validatePass, trigger: 'blur' }],
    checkPass: [{ validator: validatePass2, trigger: 'blur' }],
    age: [{ validator: checkAge, trigger: 'blur' }],
})

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

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