title: React access DOM element instead of object thru refs
body: <p>I'm trying to access DOM element in react because it need for third party library.
  And I'm able to do it with refs for built in react elems.
  Like <code>&lt;div ref={this.someRef}</code> <code>&lt;span ref={this.otherRef}</code> etc.</p>
  
  <p>And I can access DOM elem thru <code>this.someRef.current</code>
  But when I'm trying to do same trick for custom elements <code>&lt;SomeCustomElem ref={this.anotherRef}</code>, <code>this.anotherRef.current</code> returns me an object of values and I dont see any way to access DOM elem with custom components.</p>
  
  <p>Is there any chance to get access to DOM of custom elem?</p>