import React, { Component } from 'react'; class App extends Component { constructor(props) { super(props); this.sayHello = this.sayHello.bind(this); } sayHello() { alert('Hello!'); } return ( <button onClick={this.sayHello}> Click me! </button> ); } export default App;
import React from 'react'; const App = () => { const message = () => { console.log("Hello World!") } return ( <button onClick={message}> Press me to print a message! </button> ); }
<button onClick={sayHello}>Click</button>