useState

setUserInput((prevState) => {
  return { ...prevState, enteredTitle : event.target.value };
  });

callback function 으로 순서를 보장 후 보내준다.

오늘의 연습 React

import React, { useState } from 'react';

import './styles.css';

// don't change the Component name "App"
export default function App() {
    
    const [inputLengthCheck, setInputLengthCheck] = useState("Invalid message");
    const isPasswordValidHandle = (event) => {
        if (event.target.value.trim().length < 3) {
            setInputLengthCheck('Invalid message');
        }else {
            setInputLengthCheck('Valid message');
        }
    };
    return (
        <form>
            <label>Your message</label>
            <input type="text" onChange={isPasswordValidHandle}/>
            <p>{inputLengthCheck}</p>
        </form>
    );
}