socket.io/examples/ReactNativeExample/App.tsx

/**
 * Sample React Native App
 * https://github.com/facebook/react-native
 *
 * @format
 */

import React from 'react';
import type {PropsWithChildren} from 'react';
import {
  SafeAreaView,
  ScrollView,
  StatusBar,
  StyleSheet,
  Text,
  useColorScheme,
  View,
} from 'react-native';
import { socket } from './socket';
import { useEffect, useState } from 'react';

import {
  Colors,
  DebugInstructions,
  Header,
  LearnMoreLinks,
  ReloadInstructions,
} from 'react-native/Libraries/NewAppScreen';

type SectionProps = PropsWithChildren<{
  title: string;
}>;

function Section({children, title}: SectionProps): React.JSX.Element {
  const isDarkMode = useColorScheme() === 'dark';
  return (
    <View style={styles.sectionContainer}>
      <Text
        style={[
          styles.sectionTitle,
          {
            color: isDarkMode ? Colors.white : Colors.black,
          },
        ]}>
        {title}
      </Text>
      <Text
        style={[
          styles.sectionDescription,
          {
            color: isDarkMode ? Colors.light : Colors.dark,
          },
        ]}>
        {children}
      </Text>
    </View>
  );
}

function App(): React.JSX.Element {
  const [isConnected, setIsConnected] = useState(false);
  const [transport, setTransport] = useState('N/A');

  useEffect(() => {
    if (socket.connected) {
      onConnect();
    }

    function onConnect() {
      setIsConnected(true);
      setTransport(socket.io.engine.transport.name);

      socket.io.engine.on('upgrade', (transport) => {
        setTransport(transport.name);
      });
    }

    function onDisconnect() {
      setIsConnected(false);
      setTransport('N/A');
    }

    socket.on('connect', onConnect);
    socket.on('disconnect', onDisconnect);

    return () => {
      socket.off('connect', onConnect);
      socket.off('disconnect', onDisconnect);
    };
  }, []);

  return (
    <View style={styles.container}>
      <Text>Status: { isConnected ? 'connected' : 'disconnected' }</Text>
      <Text>Transport: { transport }</Text>
    </View>
  );
}

const styles = StyleSheet.create({
  sectionContainer: {
    marginTop: 32,
    paddingHorizontal: 24,
  },
  sectionTitle: {
    fontSize: 24,
    fontWeight: '600',
  },
  sectionDescription: {
    marginTop: 8,
    fontSize: 18,
    fontWeight: '400',
  },
  highlight: {
    fontWeight: '700',
  },
});

export default App;