how to get a value into a react component

1class NameForm extends React.Component {
2  constructor(props) {
3    super(props);
4    this.handleSubmit = this.handleSubmit.bind(this);
5    this.input = React.createRef();
6  }
7
8  handleSubmit(event) {
9    alert('A name was submitted: ' + this.input.current.value);
10    event.preventDefault();
11  }
12
13  render() {
14    return (
15      <form onSubmit={this.handleSubmit}>
16        <label>
17          Name:
18          <input type="text" ref={this.input} />
19        </label>
20        <input type="submit" value="Submit" />
21      </form>
22    );
23  }
24}