类型“ RefObject <HTMLDivElement>”上不存在属性“包含”。反应打字稿

Question

尝试使用此代码中的包含内容。

if (this.wrapperRef && !this.wrapperRef.contains(event.target)) {
      alert("You clicked outside of me!");
    }

export interface DatePickerProps {
  wrapperRef?: any;
}

export class DatePicker extends React.Component<DatePickerProps> {
  private wrapperRef: React.RefObject<HTMLDivElement>;
  constructor(props: DatePickerProps) {
    super(props);
    this.wrapperRef = React.createRef();
    this.handleClickOutside = this.handleClickOutside.bind(this);
  }

  componentDidMount() {
    document.addEventListener("mousedown", (e: Event) =>
      this.handleClickOutside(e)
    );
  }

  handleClickOutside(event: Event) {
    if (this.wrapperRef && !this.wrapperRef.contains(event.target)) {
      alert("You clicked outside of me!");
    }
  }
  render() {
    return <div ref={this.wrapperRef}>{this.props.children}</div>;
  }
}

export default DatePicker;

我需要.contains告诉我节点的存在。