How to use the react-native.AppRegistry.registerComponent function in react-native

/** @format */

import { AppRegistry } from "react-native";
import App from "./App";
import { name as appName } from "./app.json";

AppRegistry.registerComponent(appName, () => App);

/**
 * https://github.com/yohnz/maoyanFilm
 */

import React, {
    AppRegistry,
    Component,
    StyleSheet,
    Text,
    View,
} from 'react-native';

import film from "./main"

AppRegistry.registerComponent('film', () => film);

import { AppRegistry } from 'react-native';

import main from './main';

AppRegistry.registerComponent('ReduxFormExample', () => main);

flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#000',
  },
  box: {
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#C53938',
    height: 100,
    width: 100,
    overflow: 'hidden'
  },
});

AppRegistry.registerComponent('WaveFun', () => WaveFun);

import { ApolloProvider } from 'react-apollo'

const Client = () => {
  const networkInterface = createNetworkInterface({
    uri: 'http://localhost:8080/graphql'
  })
  const client = new ApolloClient({
    networkInterface
  });
  return (
    
      
    )
}

AppRegistry.registerComponent('apolloclient', () => Client);

/**
 * @format
 */

import {AppRegistry} from 'react-native';
import App from './App';
import {name as appName} from './app.json';

AppRegistry.registerComponent(appName, () => App);

alignItems: 'center',
    backgroundColor: '#F5FCFF',
  },
  welcome: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10,
  },
  instructions: {
    textAlign: 'center',
    color: '#333333',
    marginBottom: 5,
  },
});

AppRegistry.registerComponent('example', () => example);

import HomeView from './components/HomeView';

export default class Application extends Component {
  componentDidMount() {
    StatusBar.setBarStyle('default');
  }
  render() {
    return (
      
    );
  }
}

AppRegistry.registerComponent('RNBackgroundGeolocationSample', () => Application);

alignItems: 'center',
    backgroundColor: '#F5FCFF'
  },
  welcome: {
    fontSize: 20,
    textAlign: 'center',
    margin: 10
  },
  instructions: {
    textAlign: 'center',
    color: '#333333',
    marginBottom: 5
  }
})

AppRegistry.registerComponent('GestureViewExample', () => GestureViewExample)

);
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    alignItems: 'center',
    backgroundColor: '#F5FCFF',
  },
});

AppRegistry.registerComponent('ComparisonSlider', () => Index);