set-state-doesnt-immediately-mutate-state.js

class MyForm extends React.Component {
  constructor(props) {
    super(props);
    this.state = { message: "Hello, World" };
  }
  
  render() {
    const input = React.createElement('input', {
      type: 'text',
      value: this.state.message,
      onChange: ::this.handleChange
    });
    
    return React.createElement('div', {}, [
      input,
      this.state.message
     ]);
  }
  
  handleChange(event) {
    this.setState({ message: event.target.value });
    console.log(this.state);
  }
}

ReactDOM.render(
  React.createElement(MyForm),
  document.getElementById('root'));