How to make a working calculator in hydrogen

Hi, i started working with hydrogen yesterday and i want to make a working calculator that gives me the input back.

This is the code that i have right now but on the site it gives a error. How do i fix this?

export function Calculator() {
class FlavorForm extends React.Component {
constructor(props) {
super(props);
this.state = {value: ‘coconut’};

this.handleChange = this.handleChange.bind(this);
this.handleSubmit = this.handleSubmit.bind(this);
}

handleChange(event) {
this.setState({value: event.target.value});
}

handleSubmit(event) {
alert('Your favorite flavor is: ’ + this.state.value);
event.preventDefault();
}

render() {
return (

Pick your favorite flavor: ); } } }