title: What is the correct proptype for a ref in React?
body: <p>I am storing a ref in my redux store and using mapStateToProps to expose the ref for components that need access to it.</p>
  
  <p>The ref that is stored looks like:</p>
  
  <pre><code>ref={node =&gt; this.myRefToBePutInReduxGlobalStore = node}
  </code></pre>
  
  <p>What is the correct propType for this ref? </p>