反应：state 变量不变，setState 未触发

Question

Here is my code. The confirm state variable on line 34 will not change. Calling setConfirm from handleSubmit does not change it. I've attempted deliberately toggling it in dev tools, no effect. I've tried deliberately setting it to true in the code, and placing {confirm && <h1>TEST</h1>} at the top of the contact form. It doesn't render the h1, even when deliberately set to true. But {true && <h1>TEST</h1>} works just fine. It's as if the confirm variable doesn't even exist. Can someone shed some light on why this might be happening?

import { useState, useEffect } from 'react'
import styles from "./ContactAndBooking.module.css"

const ContactAndBooking = () => {
    // Contact form values
    const [contact, setContact] = useState({
        name: null,
        email: null,
        phone: null,
        reason: null,
        message: null
    })

    // Booking form values
    const [booking, setBooking] = useState({
        name: null,
        email: null,
        phone: null,
        date: null,
        time: null,
        description: null
    })

    // Store today's date, calendar selection minimum
    const [minDate, setMinDate] = useState()

    // Display contact form or booking form, switch on button press
    const [typeContact, setTypeContact] = useState("contact")

    // Flag invalid form values for validation alerts
    const [validFlag, setValidFlag] = useState(true)

    // Successful message confirmation flag
    const [confirm, setConfirm] = useState(false)

    // Keep track of today's date, booking calendar selection minimum
    useEffect(()=> {
        let today = new Date
        let dd = today.getDate()
        let mm = today.getMonth() + 1
        let yyyy = today.getFullYear()

        if (dd < 10)
            dd = '0' + dd
        if (mm < 10)
            mm = '0' + mm

        today = yyyy + '-' + mm + '-' + dd
        setMinDate(today)
    })

    // Validate form values
    const validate = () => {
        // Track and return form validity, switch to false if any field fails
        let isValid = true

        // Check validity of contact form values
        if (typeContact === "contact"){
            // If no name, trigger invalid flag
            if (!contact.name){
                isValid = false
            }
            // If no email or email does not match regex, trigger invalid flag
            if (!contact.email || !contact.email.match(/^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/)){
                isValid = false
            }
            // If phone number length is neither 10 nor 11 digits long, trigger invalid flag
            if (!contact.phone || ![10,11].includes(contact.phone.split('-').join('').split('').length) || contact.phone.split('-').join('').split('').some(e => !'0123456789'.includes(e))){
                isValid = false
            }
            // If no reason for contact is given, trigger invalid flag
            if (!contact.reason){
                isValid = false
            }
            // If message field is blank, trigger invalid flag
            if (!contact.message){
                isValid = false
            }
        }
        // Check validity of booking form values
        else if (typeContact === "booking"){
            // If no name, trigger invalid flag
            if (!booking.name){
                isValid = false
            }
            // If no email or email does not match regex, trigger invalid flag
            if (!booking.email || !booking.email.match(/^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/)){
                isValid = false
            }
            // If phone number length is neither 10 nor 11 digits long, trigger invalid flag
            if (!booking.phone || ![10,11].includes(booking.phone.split('-').join('').split('').length)|| booking.phone.split('-').join('').split('').some(e => !'0123456789'.includes(e))){
                isValid = false
            }
            // If no booking date is selected, trigger invalid flag
            if (!booking.date){
                isValid = false
            }
            // If no booking time is selected, trigger invalid flag
            if (!booking.time){
                isValid = false
            }
            // If no booking description is given, trigger invalid flag
            if (!booking.description){
                isValid = false
            }
        }

        // set form validation alert flag on validation failure
        !isValid ? setValidFlag(false) : setValidFlag(true)

        return isValid
    }

    const handleSubmit = (e) => {
        e.preventDefault()
        setValidFlag(true)
        if (validate()){
            console.log("CONFIRMATION TRIGGERING...") // TESTING
            // Trigger confirmation window
            setConfirm(true) // NOT TRIGGERING
            console.log("CONFIRMATION TRIGGERED") // TESTING
            if (typeContact === "contact"){
                // To be replaced with Axios request
                console.log(contact)
            }
            else if (typeContact === "booking"){
                // To be replaced with Axios request
                console.log(booking)
            }
        }
        // set form validation alert flag on validation failure
        else {
            setValidFlag(false)
            console.log("SUBMISSION INVALID")
        }
    }

    // Contact form view
    const contactWindow = () => {
        return (
            <form onSubmit={e => handleSubmit(e)}>
                {confirm && <h1>TEST</h1>}
                <label className={styles.label} htmlFor="name">Name: </label>
                <input 
                    className={styles.input} 
                    name="name" 
                    type="text" 
                    onChange={e => setContact({...contact, name: e.target.value})} 
                />
                <span className={!validFlag && !contact.name ? styles.warning : styles.warningHidden}>Please enter your name.</span>
                <label className={styles.label} htmlFor="email">Email: </label>
                <input 
                    className={styles.input} 
                    name="email" 
                    type="email" 
                    onChange={e => setContact({...contact, email: e.target.value})} 
                />
                <span className={
                    !validFlag && (!contact.email || !contact.email.match(/^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/))
                    ? styles.warning
                    : styles.warningHidden
                }>
                    Please enter a valid email address.
                </span>
                <label className={styles.label} htmlFor="phone">Phone: </label>
                <input 
                    className={styles.input} 
                    name="phone" 
                    type="text" 
                    onChange={e => setContact({...contact, phone: e.target.value})} 
                />
                <span className={
                    !validFlag && (!contact.phone || ![10,11].includes(contact.phone.split('-').join('').split('').length) || contact.phone.split('-').join('').split('').some(e => !'0123456789'.includes(e)))
                    ? styles.warning
                    : styles.warningHidden
                }>Please enter a valid phone number.</span>}
                <select 
                    className={styles.select} 
                    onChange={e => setContact({...contact, reason: e.target.value})}
                    defaultValue="Reason for contact"
                >
                    <option className={styles.option} value="Reason for contact" disabled>Reason for contact</option>
                    <option className={styles.option} value="Business Inquiry">Business Inquiry</option>
                    <option className={styles.option} value="Ticket Sales">Ticket Sales</option>
                    <option className={styles.option} value="Other">Other</option>
                </select>
                <span className={!validFlag && !contact.reason ? styles.warning : styles.warningHidden}>Please select a reason for contact.</span>
                <textarea 
                    className={`${styles.textarea} ${styles.textareaContact}`} 
                    placeholder="How can I help you?" 
                    onChange={e => setContact({...contact, message: e.target.value})} 
                />
                <span className={!validFlag && !contact.message ? styles.warning : styles.warningHideen}>Please enter your message.</span>
                <button className={styles.submit} role="submit">Submit</button>
            </form>
        )
    }

    // Booking form view
    const bookingWindow = () => {
        return (
            <form onSubmit={handleSubmit}>
                <label className={styles.label} htmlFor="name">Name: </label>
                <input 
                    className={styles.input} 
                    name="name" 
                    type="text" 
                    onChange={e => setBooking({...booking, name: e.target.value})} 
                />
                <span className={!validFlag && !booking.name ? styles.warning : styles.warningHidden}>Please enter your name.</span>
                <label className={styles.label} htmlFor="email">Email: </label>
                <input 
                    className={styles.input} 
                    name="email" 
                    type="email" 
                    onChange={e => setBooking({...booking, email: e.target.value})} 
                />
                <span className={
                    !validFlag && (!booking.email || !booking.email.match(/^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/))
                    ? styles.warning
                    : styles.warningHidden
                }>
                    Please enter a valid email address.
                </span>
                <label className={styles.label} htmlFor="phone">Phone: </label>
                <input 
                    className={styles.input} 
                    name="phone" 
                    type="text" 
                    onChange={e => setBooking({...booking, phone: e.target.value})} 
                />
                <span className={
                    !validFlag && (!booking.phone || ![10,11].includes(booking.phone.split('-').join('').split('').length)|| booking.phone.split('-').join('').split('').some(e => !'0123456789'.includes(e)))
                    ? styles.warning
                    : styles.warningHidden
                }>
                    Please enter a valid phone number.
                </span>
                <label className={styles.label} htmlFor="date">Select Date: </label>
                <input
                    className={styles.datetime} 
                    type="date" 
                    name="date"
                    min={minDate}
                    onChange={e => setBooking({...booking, date: e.target.value})} 
                />
                <span className={!validFlag && !booking.date ? styles.warning : styles.warningHidden}>Please select a date for your event.</span>
                <label className={styles.label} htmlFor="time">Select Time: </label>
                <input
                    className={styles.datetime} 
                    type="time"
                    name="time"
                    onChange={e => setBooking({...booking, time: e.target.value})}
                />
                <span className={!validFlag && !booking.time ? styles.warning : styles.warningHidden}>Please select a time for your event.</span>
                <textarea 
                    className={`${styles.textarea} ${styles.textareaBooking}`} 
                    placeholder="Please give a brief description of your event." 
                    onChange={e => setBooking({...booking, description: e.target.value})} 
                />
                <span className={!validFlag && !booking.description ? styles.warning : styles.warningHidden}>Please describe your event.</span>
                <button className={styles.submit} role="submit">Submit</button>
            </form>
        )
    }

    // Message confirmation window, triggered on successful validation and submission
    const confirmWindow = () => {
        return (
            <div className={styles.confirmContainer}>
                <h1 className={`${styles.confirmText} ${styles.confirmThankYou}`}>Thanks for the message!</h1>
                <h3 className={`${styles.confirmText} ${styles.confirmSubThankYou}`}>I'll get back to you ASAP.</h3>
                <button className={styles.confirmOkay} onClick={setConfirm(false)}>Okay</button>
            </div>
        )
    }

    return (
        <div className={styles.container} id="contact">
            <button 
                role="button"
                className={`${styles.toggle} ${styles.toggleContact}`} 
                onClick={() => {
                    setTypeContact("contact")
                    setValidFlag(true)
                }}
            >
                CONTACT
            </button>
            <button 
                role="button"
                className={`${styles.toggle} ${styles.toggleBooking}`} 
                onClick={() => {
                    setTypeContact("booking")
                    setValidFlag(true)
                }}
            >
                BOOKING
            </button>
            <br />
            {typeContact === "contact" && contactWindow()}
            {typeContact === "booking" && bookingWindow()}
            {confirm && confirmWindow()}
        </div>
    )
}

export default ContactAndBooking

Answer 1

try changing line 273 from

<button className={styles.confirmOkay} onClick={setConfirm(false)}>Okay</button>

to

<button className={styles.confirmOkay} onClick={() => setConfirm(false)}>Okay</button>

then it appears to be working

Answer 2

When you call setConfirm(false) in your onClick event, what you are actually saying is to run the setConfirm state update as soon as the page loads. What you want to do is create an arrow function in the onClick so that you are passing reference to a function that will be ran once the button is clicked.

<button className={styles.confirmOkay} onClick={() => setConfirm(false)}>Okay</button>

If you wanted to do more than just call setConfirm, you can create another function and call setConfirm inside of that, then you can just pass the new function as reference so that every time the button is clicked the setConfirm function gets called.

const handleConfirmUpdate = () => {
   // do some stuff in here if you'd like
   setConfirm(true);
}

<button className={styles.confirmOkay} onClick={handleConfirmUpdate}>Okay</button>

Notice that we are not calling the function, but rather passing a reference.