PeerLite

This is a fork of peer-lite - thanks to skyllo for the base code.

This fork adds the ability to optionally stop the tracks of a stream when removing it from a peer. This behaviour is on by default, but can be disabled by passing false as the third argument to removeStream or any other relevant method.

Lightweight WebRTC browser library that supports video, audio and data channels.

Features

• Lightweight! 3kb (gzipped)
• Zero dependencies
• Ships with TypeScript definitions
• Uses modern WebRTC APIs
• "Perfect negotiation" pattern
• Support for renegotiation of connection
• ICE candidate batching

Installation

yarn add peer-lite

Usage

Two peers connecting locally

import Peer from 'peer-lite';

const peer1 = new Peer();
const peer2 = new Peer();

peer1.on('signal', async (description) => {
  await peer2.signal(description);
})

peer2.on('signal', async (description) => {
  await peer1.signal(description);
})

peer1.on('onicecandidates', async (candidates) => {
  const promises = candidates.map(async candidate => peer2.addIceCandidate(candidate));
  await Promise.all(promises);
});

peer2.on('onicecandidates', async (candidates) => {
  const promises = candidates.map(async candidate => peer1.addIceCandidate(candidate));
  await Promise.all(promises);
});

peer1.on('streamRemote', (stream) => {
  document.querySelector('#video1').srcObject = stream;
});

peer2.on('streamRemote', (stream) => {
  document.querySelector('#video2').srcObject = stream;
});

(async () => {
  const stream = await Peer.getUserMedia();
  peer1.addStream(stream);
  peer2.addStream(stream);
  peer1.start();
})();

Peer connection with fake signalling server

import Peer from 'peer-lite';

const peer = new Peer();
const fakeSocket = new Socket();

// Peer events

peer.on('signal', async (description) => {
  fakeSocket.emit('signal', description);
});

peer.on('onicecandidates', async (candidates) => {
  fakeSocket.emit('onicecandidates', candidates);
});

peer.on('streamLocal', (stream) => {
  document.querySelector('#videoLocal').srcObject = stream;
});

peer.on('streamRemote', (stream) => {
  document.querySelector('#videoRemote').srcObject = stream;
});

// Socket events

fakeSocket.on('signal', async (description) => {
  await peer.signal(description);
});

fakeSocket.on('onicecandidates', async (candidates) => {
  const promises = candidates.map(async candidate => peer.addIceCandidate(candidate));
  await Promise.all(promises);
});

(async () => {
  const stream = await Peer.getUserMedia();
  peer.addStream(stream);
  peer.start();
})();

Examples

See more examples here with signalling server.

API

Constructor

new Peer(Options)

Peer Options

interface PeerOptions {
  /** Enable support for batching ICECandidates */
  batchCandidates?: boolean;
  /** Timeout in MS before emitting batched ICECandidates */
  batchCandidatesTimeout?: number;
  /** Peer id used when emitting errors */
  id?: string;
  /** RTCPeerConnection options */
  config?: RTCConfiguration;
  /** RTCOfferOptions options */
  offerOptions?: RTCOfferOptions;
  /** Enable support for RTCDataChannels */
  enableDataChannels?: boolean;
  /** Default RTCDataChannel label */
  channelLabel?: string;
  /** Default RTCDataChannel options */
  channelOptions?: RTCDataChannelInit;
  /** Function to transform offer/answer SDP */
  sdpTransform?: (sdp: string) => string;
}

Peer API

interface Peer {
  /** Create a peer instance */
  constructor(options?: PeerOptions);
  /** Initialize the peer */
  init(): RTCPeerConnection;
  /** Start the RTCPeerConnection signalling */
  start({ polite }?: {
      polite?: boolean | undefined;
  }): void;
  /** Process a RTCSessionDescriptionInit on peer */
  signal(description: RTCSessionDescriptionInit): Promise<void>;
  /** Add RTCIceCandidate to peer */
  addIceCandidate(candidate: RTCIceCandidate): Promise<void>;
  /** Send data to connected peer using an RTCDataChannel */
  send(data: string | Blob | ArrayBuffer | ArrayBufferView, label?: string): boolean;
  /** Add RTCDataChannel to peer */
  addDataChannel(label?: string, options?: RTCDataChannelInit): void;
  /** Get RTCDataChannel added to peer */
  getDataChannel(label?: string): RTCDataChannel | undefined;
  /** Close peer if active */
  destroy(): void;
  /** Return the ICEConnectionState of the peer */
  status(): RTCIceConnectionState;
  /** Return true if the peer is connected */
  isConnected(): boolean;
  /** Return true if the peer is closed */
  isClosed(): boolean;
  /** Return the RTCPeerConnection */
  get(): RTCPeerConnection;
  /** Return the local stream */
  getStreamLocal(): MediaStream;
  /** Add stream to peer, optionally replacing existing streams, and stopping existing tracks */
  addStream(stream: MediaStream, replace?: boolean, stopTracks?: boolean): void;
  /** Remove stream from peer */
  removeStream(stream: MediaStream, stopTracks?: boolean): void;
  /** Add track to peer */
  addTrack(track: MediaStreamTrack): void;
  /** Remove track on peer */
  removeTrack(track: MediaStreamTrack, stopTrack?: boolean): void;
  /** Remove tracks on peer */
  removeTracks(tracks: MediaStreamTrack[], stopTracks?: boolean): void;
  /** Replace track with another track on peer */
  replaceTrack(track: MediaStreamTrack, newTrack: MediaStreamTrack, stopOldTrack?: boolean): Promise<void>;
  on<E extends keyof PeerEvents>(event: E, listener: PeerEvents[E]): TypedEmitter<PeerEvents>;
  off<E extends keyof PeerEvents>(event: E, listener: PeerEvents[E]): TypedEmitter<PeerEvents>;
  offAll<E extends keyof PeerEvents>(event?: E): TypedEmitter<PeerEvents>;
}

Peer Events

interface PeerEvents {
  error: (data: { id: string; message: string; error?: Error }) => void;
  // Connection Status
  connecting: VoidFunction;
  connected: VoidFunction;
  disconnected: VoidFunction;
  status: (status: RTCIceConnectionState) => void;
  // Signal and RTCIceCandidates
  signal: (description: RTCSessionDescriptionInit) => void;
  onicecandidates: (iceCandidates: RTCIceCandidate[]) => void;
  // MediaStreams
  streamLocal: (stream: MediaStream) => void;
  streamRemote: (stream: MediaStream) => void;
  // RTCDataChannel
  channelOpen: (data: { channel: RTCDataChannel }) => void;
  channelClosed: (data: { channel: RTCDataChannel }) => void;
  channelError: (data: { channel: RTCDataChannel; event: RTCErrorEvent }) => void;
  channelData: (data: {
    channel: RTCDataChannel;
    source: 'incoming' | 'outgoing';
    data: string | Blob | ArrayBuffer | ArrayBufferView;
  }) => void;
}

Testing

The tests run inside a headless Chrome and Firefox with Playwright and @playwright/test. These run quickly and allow testing of WebRTC APIs in real browsers.

Run Tests (Chrome only)

yarn test

Run Tests (Chrome + Firefox)

CI=true yarn test

Similar Projects

• PeerJS: https://github.com/peers/peerjs
• Simple Peer: https://github.com/feross/simple-peer
• SimpleWebRTC: https://github.com/andyet/SimpleWebRTC
• More here: https://stackoverflow.com/questions/24857637/current-state-of-javascript-webrtc-libraries