title: How to pass a component's function to a component inside of navigationoptions
body: <p>so I've been dealing with this problems for days now and have been googling a lot and trying to implement a solution. Most solutions suggest using 
  <code>this.props.navigation.setParams({function: this.function.bind(this))</code> inside of <code>componentDidMount</code> and then doing something like this in navigationOptions -> </p>
  
  <pre><code>static navigationOptions = {
  header:  ({navigation})  =&gt; 
     &lt;Button onPress = { () =&gt; navigation.state.params.function}/&gt; }
  </code></pre>
  
  <p>This works for buttons with onPress but this method doesn't seem to work when it's just a 'props' to a Custom Component. </p>
  
  <p>This is my code </p>
  
  <pre><code>static navigationOptions = {
  header:  ({navigation})  =&gt; 
     &lt;CustomCar refreshCar = {navigation.state.params.refreshCarSearch}
     /&gt;
  
  transitionConfig: () =&gt; ({
    transitionSpec: {
      duration: 0,
      timing: Animated.timing,
      easing: Easing.step0,
    },
  }),
  };
  
  constructor(props) {
      super(props)
      this.state =  {
        Car: ' '
      }
      this.refreshCarSearch = this.refreshCarSearch.bind(this);
  }
  
  componentDidMount() {
  this.props.navigation.setParams({ refreshCarSearch: this.refreshCarSearch });
                 }
  
  refreshCarSearch(e){
      this.setState({
          Car: e
          });
                  }
  </code></pre>
  
  <p>I always get navigation.state.params.refreshCarSearch is undefined. I've tried a lot of variations of this method but to no avail. This method only works if I replace the component with a button with onPress, but I need to pass this function over. Basically, I need to have my CustomCar component (which must reside at the top of the screen, so in navigationOptions) pass a value back to this Component so refreshCarSearch can happen. The only way I've read how to do this is with Redux or this case where the parent component passes the refreshCarSearch function to the 'child' component. The component existing in navigationOptions makes it much more difficult, is this possible? </p>