React代码找错试题 求助

[Z.Chen]

class VaisalaDummyComponent extends React.Component {
    constructor(props) {
        // set the default internal state
        this.state = {
            clicks: 0
        };
    }

    componentDidMount() {
        this.refs.vaisalaComponentDiv.addEventListener('click', this.clickHandler);
    }

    componentWillUnmount() {
        this.refs.vaisalaComponentDiv.removeEventListener('click', this.clickHandler);
    }

    clickHandler() {
        this.setState({
            clicks: this.clicks + 1
        });
    }

    render() {
        let children = this.props.children;
        return (
            <div className="Vaisala-dummy-component" ref="vaisalaComponentDiv">
                <h2>Vaisala Component ({this.state.clicks} clicks})</h2>
                <h3>{this.props.headerText}</h3>
                {children}
            </div>
        );
    }
}

请问上述代码哪里有问题啊？

[FnaticE]

super(props);是不是漏了？