function findDOMNode(componentOrElement) {
	  if ("production" !== process.env.NODE_ENV) {
	    var owner = ReactCurrentOwner.current;
	    if (owner !== null) {
	      ("production" !== process.env.NODE_ENV ? warning(
	        owner._warnedAboutRefsInRender,
	        '%s is accessing getDOMNode or findDOMNode inside its render(). ' +
	        'render() should be a pure function of props and state. It should ' +
	        'never access something that requires stale data from the previous ' +
	        'render, such as refs. Move this logic to componentDidMount and ' +
	        'componentDidUpdate instead.',
	        owner.getName() || 'A component'
	      ) : null);
	      owner._warnedAboutRefsInRender = true;
	    }
	  }
	  if (componentOrElement == null) {
	    return null;
	  }
	  if (isNode(componentOrElement)) {
	    return componentOrElement;
	  }
	  if (ReactInstanceMap.has(componentOrElement)) {
	    return ReactMount.getNodeFromInstance(componentOrElement);
	  }
	  ("production" !== process.env.NODE_ENV ? invariant(
	    componentOrElement.render == null ||
	    typeof componentOrElement.render !== 'function',
	    'Component (with keys: %s) contains `render` method ' +
	    'but is not mounted in the DOM',
	    Object.keys(componentOrElement)
	  ) : invariant(componentOrElement.render == null ||
	  typeof componentOrElement.render !== 'function'));
	  ("production" !== process.env.NODE_ENV ? invariant(
	    false,
	    'Element appears to be neither ReactComponent nor DOMNode (keys: %s)',
	    Object.keys(componentOrElement)
	  ) : invariant(false));
	}
Returns the DOM node rendered by this element.

@param {ReactComponent|DOMElement} componentOrElement
@return {DOMElement} The root node of this element.