constructor(props) {

super(props);

this.state = { loading: false, msg: null };

}

handleClick = e => {

e.preventDefault();

this.setState({ loading: true });

fetch('/.netlify/functions/hello')

.then(response => response.json())

.then(json => this.setState({ loading: false, msg: json.msg }));

};

render() {

const { loading, msg } = this.state;

return (

<p>

<button onClick={this.handleClick}>

{loading ? 'Loading...' : 'Call Lambda'}

</button>

<br />

<span>{msg}</span>

</p>

);

}

render() {

return (

<div className="App">

<header className="App-header">

<img src={logo} className="App-logo" alt="logo" />

<p>

Edit <code>src/App.js</code> and save to reload.

</p>

<LambdaDemo />

</header>

</div>

);

}