import React , { Component , Children } from 'react' ; import { findDOMNode } from 'react-dom' ; declare var window ; export class MDLWrapper extends Component < { } , { } > { componentDidMount ( ) { window . componentHandler . upgradeElement ( findDOMNode ( this ) ) ; } componentWillUnmount ( ) { window . componentHandler . downgradeElements ( findDOMNode ( this ) ) ; } render ( ) { return Children . only ( this . props . children ) ; } }