Reactにおけるスプレッド構文の使い所 - Qiita

import React from 'react'; import InputForm from './components/InputForm'; import UserList from './components/UserList'; class App extends React.Component { constructor() { super() this.state = { users: [] } this.addUser = this.addUser.bind(this) } addUser(inputUser) { this.setState({ // ①App.jsにおけるスプレッド構文 users: [...this.state.users, inputUser] }) } render() { return ( <div className="App" > <h1>