ReactJS 使用 MaterialUI 处理表单错误

Question

提交表单后，我想验证两个字段。具体来说，我想检查密码是否至少有 5 个字符，以及 password 和 confirmPassword 字段是否匹配。我继续实施状态来保存这些错误消息。但是，并不是所有的错误都被显示出来。示例：假设用户在密码字段中输入了 'hell'，并在密码确认中输入了 'hello'。您可能会收到 2 条错误消息（密码太短，密码不匹配），但我的表单只显示一条错误 - 密码不匹配。

我怀疑问题出在 validateFields 函数上。如果我交换 if 语句的顺序并输入我上面描述的相同输入，那么我设法看到 'password must contain at least 5 characters' 错误，但看不到“密码不匹配错误”。此外，在使用反应开发工具时，我注意到在错误状态下只设置了一条消息。所以我认为我没有正确使用 setState，也许传播运算符没有按我的预期工作？

import React, {useState} from 'react'
import {Grid, TextField, RadioGroup, Radio, FormControl, FormLabel, FormControlLabel, Checkbox, Button} from '@material-ui/core'

const Registration = () => {
    const [data, setData] = useState({
        username: '',
        email: '',
        password: '',
        confirmPassword: '',
    })

    const [errors, setErrors] = useState({
        short: '',
        mismatch: '',
    })

    const handleChange = e => {
        const value = e.target.type === 'checkbox' ? e.target.checked : e.target.value
        setData({
            ...data,
            [e.target.name]: value,
        })
    }

    const validateFields = () => {
        let error = false
        if (data.password && data.password.length < 5) {
            error = true
            console.log('password was too short')
            setErrors({...errors, short: 'Password must contain at least 5 characters'})
            console.log('short set')
        }
        if (data.confirmPassword && data.confirmPassword !== data.password) {
            error = true
            setErrors({...errors, mismatch: "Passwords don't match"})
        }
        return error
    }

    const handleSubmit = e => {
        e.preventDefault()
        console.log(data)
        if (validateFields()) {
            return
        }
    }

    return (
        <Grid id='registration-form' container xs={12} direction='column'>
            <Grid item xs={12} align='center'>
                <h1>Register</h1>
            </Grid>
            <form onSubmit={handleSubmit}>
                <Grid container spacing={2} xs={12} alignItems='center' justify='center'>
                    <Grid container item xs={3} direction='column' spacing={2}>
                        <Grid item>
                            <TextField id='username' name='username' label='Username' onChange={handleChange} value={data.username} required />
                        </Grid>
                        <Grid item>
                            <TextField id='email' name='email' label='Email' onChange={handleChange} value={data.email} required type='email' />
                        </Grid>
                        <Grid item>
                            <TextField id='password' name='password' label='Password' onChange={handleChange} value={data.password} error={errors.short !== ''} helperText={errors.short} required type='password' />
                        </Grid>
                        <Grid item>
                            <TextField
                                id='confirm-password'
                                name='confirmPassword'
                                label='Confirm Password'
                                onChange={handleChange}
                                value={data.confirmPassword}
                                error={Boolean(errors?.mismatch)}
                                helperText={errors?.mismatch}
                                required
                                type='password'
                            />
                        </Grid>
                    </Grid>
                </Grid>
            </form>
            <Grid item align='center'>
                <a href='#'>Already have an account? Login</a>
            </Grid>
        </Grid>
    )
}

export default Registration

Answer 1

通过以下代码更改您的验证函数。它会起作用。

const validateFields = () => {
    let error = false
    if (data.password && data.password.length < 5) {
        error = true
        console.log('password was too short')

        //notice updater function here
        setErrors(state=>({...state, short: 'Password must contain at least 5 characters'}))
        console.log('short set')
    }
    if (data.confirmPassword && data.confirmPassword !== data.password) {
        error = true
        setErrors(state=>({...state, mismatch: "Passwords don't match"}))
    }
    return error
}

当您的状态更新取决于以前的状态值时，传递函数而不是对象来设置状态，以确保调用始终使用状态的最新版本。传递更新函数允许您访问更新程序内部的当前状态值。

ReactJS 使用 MaterialUI 处理表单错误

ReactJS Handling Form Errors With MaterialUI

javascript

reactjs

material-ui

react-state