pico.chat/apps/screen.js

addEventListener('rpc-new', ({detail}) => {
    const {uid, kind} = detail.value
    if(kind === 'screen') {
        const sender = ScreenShare.isSource && ScreenShare.stream
        const receiver = !ScreenShare.isSource && ScreenShare.stream
        signal({kind: 'rpc-setup', value: {uid, sender, receiver}})
    }
})
const ScreenShareConfig = {
    view() {
        if (ScreenShare.isOff) {
            const onclick = ScreenShare.getStream
            return m('button', {onclick}, 'start screen sharing')
        }
        else {
            const onclick = () => wire({kind: 'screen-stop'})
            return m('button', {onclick}, 'stop screen sharing')
        }
    }
}
const ScreenShare = {
    isSource: false,
    stream: new MediaStream(),
    get isOff() {
        return ScreenShare.stream.getTracks().length === 0
    },
    async getStream() {
        await navigator.mediaDevices
            .getDisplayMedia({})
            .then(stream => stream
            .getTracks()
            .forEach(tr => ScreenShare.stream.addTrack(tr, stream))
        )
        ScreenShare.isSource = true
        State.others.forEach(target => {
            signal({kind: 'rpc-needed', value: {kind: 'screen', target}})
        })
        m.redraw()
    },
    async stopStream() {
        ScreenShare.stream.getTracks().forEach(tr => tr.stop())
        ScreenShare.stream = new MediaStream()
        ScreenShare.isSource = false
        m.redraw()
    },
    view() {
        const style = {
            overflow: 'scroll',
            backgroundColor: 'gray',
            color: 'white',
            fontFamily: 'monospace',
            position: 'relative',
        }
        return ScreenShare.isOff ? [] : m('.screen-share', {style},
            m('video[playsinline][autoplay]', {srcObject: ScreenShare.stream})
        )
    },
}
addEventListener('screen-stop', () => {
    ScreenShare.stopStream()
})
addEventListener('join', ({detail: {value: user}}) => {
    if(ScreenShare.isSource) {
        signal({kind: 'rpc-needed', value: {kind: 'screen', target: user}})
    }
})
addEventListener('load', () => {
    doNotLog.add('screen-stop')
    Headers.push([ScreenShareConfig])
    Apps.push([ScreenShare, {key: 'screen-share-container'}])
})