Question

const [count, setCount] = useState(0);

const countHandler = () => {
   setCount(prevCount => prevCount + 1)
}

return (
    <div className={styles.testclass}>
        <h2>Count Value {count}</h2>
        <button onClick={countHandler}>Update Count</button>
    </div>
)

此处计数被分解为恒定值，因此它将如何使用setCount更改值

Answer 1

对于功能组件，该功能在每次渲染期间执行。因此，将在count中创建变量useState，并使用version: '3.5' services: laravel-app: build: context: '.' container_name: my-app volumes: - ./:/var/www/html - ./docker_configs/custom.ini:/usr/local/etc/php/conf.d/custom.ini - ./docker_configs/laravel-worker.conf:/etc/supervisor/conf.d/laravel-worker.conf - ./docker_configs/docker_cron:/etc/cron.d/docker_cron working_dir: /var/www/html ports: - 8080:80 networks: backend: aliases: - app mariadb: image: mariadb:10.2 container_name: my-db volumes: - ./run/var:/var/lib/mysql environment: - MYSQL_ROOT_PASSWORD=root - MYSQL_DATABASE=${DB_DATABASE} - MYSQL_USER=${DB_USERNAME} - MYSQL_PASSWORD=${DB_PASSWORD} ports: - 3309:3306 networks: backend: aliases: - db networks: backend: name: backend-network已存储的先前渲染中的值。

使用useState（）挂钩时如何更新const变量'count'

1 个答案: