controller.js

// vim: syntax=JSX

render(){
  const { children } = this.props
  const { isOpen, style } = this.state

  const inputChildren = React.Children.map(children, child => {
    if(child.type.displayName === "Select"){
      return React.cloneElement(child, {open: this.open})
    }
    else{
      return (
        isOpen && ReactDOM.createPortal(
          <span style={style}>{React.cloneElement(child)}</span>, document.body
        )
      )
    }
  })
  return inputChildren
}