IT技术 - undefined 不是一个对象（评估'_this.props.date.getFullYear'） - 吾爱随笔录

我遇到了这样的错误：

这些是我的代码

export default class StarView extends Component{
static propTypes = {
    date : React.PropTypes.instanceOf(Date)
}
constructor(props){
    super(props);
    this.state = {
        selectedYear: this.props.date.getFullYear(),
        selectedMonth: this.props.date.getMonth(),
        selectedDate: this.props.date.getDate(),
        yesterdayYear : new Date(this.props.date.getTime() - 24 * 3600 * 1000).getFullYear(),
        yesterdayMonth: new Date(this.props.date.getTime() - 24 * 3600 * 1000).getMonth(),
        yesterdatDate : new Date(this.props.date.getTime() - 24 * 3600 * 1000).getDate(),
        tomorrowYear : new Date(this.props.date.getTime() + 24 * 3600 *1000).getFullYear(),
        tomorrowMonth : new Date(this.props.date.getTime() + 24 * 3600 *1000).getMonth(),
        tomorrowDate : new Date(this.props.date.getTime() + 24 * 3600 *1000).getDate()
    }
}}

我想从 this.props.date 获取默认数据，但我不知道我收到错误的原因

export default class StarView extends Component{ static propTypes = { date: React.PropTypes.instanceOf(Date) } static defaultProps = { date: new Date() } constructor(props){ super(props); this.state = { selectedYear: this.props.date.getFullYear(), selectedMonth: this.props.date.getMonth(), selectedDate: this.props.date.getDate(), yesterdayYear: new Date(this.props.date.getTime() - 24 * 3600 * 1000).getFullYear(), yesterdayMonth: new Date(this.props.date.getTime() - 24 * 3600 * 1000).getMonth(), yesterdatDate: new Date(this.props.date.getTime() - 24 * 3600 * 1000).getDate(), tomorrowYear: new Date(this.props.date.getTime() + 24 * 3600 *1000).getFullYear(), tomorrowMonth: new Date(this.props.date.getTime() + 24 * 3600 *1000).getMonth(), tomorrowDate: new Date(this.props.date.getTime() + 24 * 3600 *1000).getDate() } } }