React v16 中 portal 的使用

class Dialog extends React.Component {
  constructor() {
    super(...arguments)

    const doc = window.document
    this.node = doc.createElement('div')
    doc.body.appendChild(this.node)

    window.document.body.appendChild(
      window.document.createElement('div')
    )
  }

  
  componentWillUnmount() {
    window.document.body.removeChild(this.node)
  }

  render() {
    return createPortal(
      <div class='dialog'>
        {this.props.children}
      </div>,
      this.node
    )
  }
}