关于react的疑惑

<script type="text/babel">
    class Buttons extends React.Component {
        constructor(props) {
            super(props);
            this.state = {button: true};
            this.handle = this.handle.bind(this);
        }
        handle() {
            this.setState((prevState) => ({
                button: !prevState.button
            }));
        }
        render() {
            return(
            <div>
                <button onClick={this.handle}>
                    {this.state.button?‘ON‘: ‘OFF‘}
                </button>
            </div>)
        }
    }
    ReactDOM.render(
        <Buttons/>,
        document.getElementById(‘example‘)
    );
</script>