你这写法看不懂... 一般不都是这么写的吗?

class Main extends Component {
constructor(props) {
super(props);
this.state = {
value: 0,
chartIndex: 0,
};
this.handleChange = this.handleChange.bind(this);
this.draw = this.draw.bind(this);
}

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

draw(index) {
return (
<Chart data={this.props.data[index]}></Chart>
);
};

render() {
var options = <></>
for (let i = 0; i < this.props.childrenNumber; i++) {
options = <>{options}<option value={i}>{i+1}</option></>
}
const {chartIndex} = this.state
return (
<div>
<select value={this.state.value} onChange={this.handleChange}>
{options}</select>
{this.draw(chartIndex)}
</div>
)
}
}