title: Should I remove a reference to a DOM element when a component unmount in react?
body: <p>I have a react component which take a dom reference when mounting (I know this is an edge case). I would like to know if it is necessary set to <code>null</code> the property which host the dom. Or does react take care of it?</p>
  
  <pre><code>componentDidMount() {
     this.elm = document.getElementById('foo')
  }
  
  componentWillUnmount(){
     this.elm = null
  }
  </code></pre>