pico.chat/apps/rpc.js

const allStreams = {}

// https://stackoverflow.com/a/2117523
function uuidv4() {
  return ([1e7]+-1e3+-4e3+-8e3+-1e11).replace(/[018]/g, c =>
    (c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16)
  )
}

function newRPC(uid, target) {
    const rpc = new RTCPeerConnection(rpcConfig)
    rpc.onicecandidate = ({candidate}) => {
        if(candidate && candidate.candidate) {
            const value = JSON.parse(JSON.stringify(candidate))
            wire({kind: 'ice-candidate', value: {...value, uid}, target})
        }
    }
    rpc.ontrack = ({streams: [stream]}) => {
        stream.getTracks().forEach(tr => ScreenShare.stream.addTrack(tr, stream))
    }
    rpc.onconnectionstatechange = () => {
        console.log(rpc.connectionState)
    }
    return rpc
}

addEventListener('screen-start', async ({detail}) => {
    const {target, stream} = detail.value
    const uid = uuidv4()
    const rpc = newRPC(uid, target)
    allStreams[uid] = {target, rpc}

    stream.getTracks().forEach(tr => rpc.addTrack(tr, stream))
    const localOffer = await rpc.createOffer()
    await rpc.setLocalDescription(localOffer)

    wire({kind: 'screen-offer', value: {...localOffer, uid}, target})
})

addEventListener('screen-offer', async ({detail}) => {
    const target = detail.source
    const uid = detail.value.uid
    const rpc = newRPC(uid, target)
    allStreams[uid] = {target, rpc}

    await rpc.setRemoteDescription(detail.value)
    const localAnswer = await rpc.createAnswer()
    await rpc.setLocalDescription(localAnswer)

    wire({kind: 'screen-answer', value: {...localAnswer, uid}, target})
})

addEventListener('screen-answer', async ({detail}) => {
    await allStreams[detail.value.uid].rpc.setRemoteDescription(detail.value)
})

addEventListener('ice-candidate', async ({detail}) => {
    await allStreams[detail.value.uid].rpc.addIceCandidate(detail.value)
})

addEventListener('load', () => {
    doNotLog.add('screen-start')
    doNotLog.add('screen-offer')
    doNotLog.add('screen-answer')
    doNotLog.add('ice-candidate')
})