Video call in react-native

Help
1

I want to make the video call with this package (react-native-webrtc).
I followed the code in the doc, But I can only turn on the camera.
I think there are other steps that I miss to make video call with this package.
I need the sample code or any advices.

My code:

import React, {Component} from 'react';
import {View, Text, StyleSheet, Platform} from 'react-native';
import {
  RTCPeerConnection,
  RTCIceCandidate,
  RTCSessionDescription,
  RTCView,
  MediaStream,
  MediaStreamTrack,
  mediaDevices,
  registerGlobals,
} from 'react-native-webrtc';

class VideoChat extends Component {
  state = {
videoURL: null,
isFront: false,
  };

  componentDidMount() {
const configuration = {iceServers: [{url: 'stun:stun.l.google.com:19302'}]};
const pc = new RTCPeerConnection(configuration);
const {isFront} = this.state;
mediaDevices.enumerateDevices().then((sourceInfos) => {
  console.log('mediaDevices.enumerateDevices()', sourceInfos);
  let videoSourceId;
  for (let i = 0; i < sourceInfos.length; i++) {
    const sourceInfo = sourceInfos[i];
    if (
      sourceInfo.kind === 'videoinput' &&
      sourceInfo.facing === (isFront ? 'front' : 'environment')
    ) {
      videoSourceId = sourceInfo.deviceId;
    }
  }
  mediaDevices
    .getUserMedia({
      audio: true,
      video: {
        video: true,
        facingMode: isFront ? 'user' : 'environment',
        optional: videoSourceId ? [{sourceId: videoSourceId}] : [],
      },
    })
    .then((stream) => {
      // Got stream!
      console.log('stream =>', stream);
      this.setState({
        videoURL: stream.toURL(),
      });
      pc.addStream(stream);
    })
    .catch((error) => {
      // Log error
      console.log('error =>', error);
    });
});

pc.createOffer().then((desc) => {
  pc.setLocalDescription(desc).then(() => {
    // Send pc.localDescription to peer
    console.log('setLocationDescription', desc);
  });
});

pc.onicecandidate = (event) => {
  // send event.candidate to peer
  console.log('onicecandidate', event);
};
  }

  render() {
const {videoURL} = this.state;
return <RTCView streamURL={videoURL} style={styles.container} />;
  }
}

const styles = StyleSheet.create({
  container: {
flex: 1,
backgroundColor: 'white',
borderWidth: 1,
borderColor: 'red',
  },
});

export default VideoChat;