tabBarIcon.js

navigationOptions: ({ navigation }) => {      
  const { routeName, routes } = navigation.state;      
  return {        
    tabBarIcon: ({ focused, tintColor }) => {          
       // You can return any component that you like here! 
       // We usually create an icon component rendering some svg        
       return <Icon type={routeName} focused={focused} />;       
    }
  }
}