render() {
    const {error, className} = this.props;

    if (!error) {
      return null;
    }

    if (supportsDetails) {
      const [summary, ...body] = error.message.split(/\n+/g);

      if (body.length >= 0) {
        return <div className={className}>{summary}</div>;
      }

      return (
        <details className={className}>
          <summary>{summary}</summary>
          {body.join('\n')}
        </details>
      );
    }

    return <div className={className}>{error.message}</div>;
  }
Prevent IE9 from raising an error on an unrecognized element:
See https://github.com/facebook/react/issues/13610