Using React.findDOMNode in TypeScript

I'm following the React Tutorial and got stuck on how to use React.findDOMNode. Here is my code: export class CommentForm extends React.Component<{}, {}> { handleSubmit(e: React.FormEvent) { e.preventDefault(); console.log(React.findDOMNode(this.refs['author'])); } render() { return <form className="commentForm" onSubmit={ e => this.handleSubmit(e) }> <input type="text" placeholder="Your name" ref