title: How to use different icons for each tab with createBottomTabNavigator?
body: <p>I am using <code>React Native Navigation v2</code> for my project. I am trying to set two different IonIcons with the <code>createBottomTabNavigator</code>.</p>
  
  <p>Their <a href="https://reactnavigation.org/docs/en/tab-based-navigation.html" rel="nofollow noreferrer">site</a> gives an example like this:</p>
  
  <pre><code>navigationOptions: ({ navigation }) =&gt; ({
    tabBarIcon: ({ focused, tintColor }) =&gt; {
      const { routeName } = navigation.state;
      let iconName;
      if (routeName === 'Home') {
        iconName = `ios-information-circle${focused ? '' : '-outline'}`;
      } else if (routeName === 'Settings') {
        iconName = `ios-options${focused ? '' : '-outline'}`;
      }
  
      // You can return any component that you like here! We usually use an
      // icon component from react-native-vector-icons
      return &lt;Ionicons name={iconName} size={25} color={tintColor} /&gt;;
    },
  }),
  </code></pre>
  
  <p>But to me, this seems dull. Can I define the IonIcon in the component itself?
  How can I define the symbols individually with React Native Navigation v2?</p>