WebRTC Tutorial : RoomScreen.js :: https://github.com/DipanshKhandelwal/react-native-webrtc-firebase/blob/master/src/screens/RoomScreen.js

RoomScreen.js

import React, { useState } from 'react';
import { Text, StyleSheet, Button, View, TextInput } from 'react-native';

export default function RoomScreen({ setScreen, screens, setRoomId, roomId }) {

  const onCallOrJoin = (screen) => {
    if (roomId.length > 0) {
      setScreen(screen)
    }
  }

  return (
    <>
      <Text style={styles.heading} >Select a Room</Text>
      <TextInput style={styles.input} value={roomId} onChangeText={setRoomId} />
      <View style={styles.buttonContainer} >
        <Button title="Join Screen" onPress={() => onCallOrJoin(screens.JOIN)} />
      </View>
      <View style={styles.buttonContainer} >
        <Button title="Call Screen" onPress={() => onCallOrJoin(screens.CALL)} />
      </View>
    </>
  )
}

const styles = StyleSheet.create({
  heading: {
    marginVertical: 10,
    alignSelf: 'center',
    fontSize: 30,
  },
  input: {
    margin: 20,
    height: 40,
    backgroundColor: '#aaa'
  },
  buttonContainer: {
    margin: 5
  }
});