How to use the react-native-webrtc.mediaDevices.enumerateDevices function in react-native-webrtc

const startLocalStream = async () => {
    const isFront = true;
    const devices = await mediaDevices.enumerateDevices();

    const facing = isFront ? 'front' : 'back';
    const videoSourceId = devices.find(device => device.kind === 'videoinput' && device.facing === facing);
    const facingMode = isFront ? 'user' : 'environment';
    const constraints = {
      audio: true,
      video: {
        mandatory: {
          minWidth: 500, // Provide your own width, height and frame rate here
          minHeight: 300,
          minFrameRate: 30,
        },
        facingMode,
        optional: videoSourceId ? [{sourceId: videoSourceId}] : [],
      },
    };

const _enumerateDevices = () => mediaDevices.enumerateDevices()