Check if someone comes online in whatsapp web

whatsapp-web-check-presence.js

var audioContext = new AudioContext();

function play(frequency) {
    var sampleRate = audioContext.sampleRate;
    var duration = 1*sampleRate;
    var numChannels = 1;
    var buffer  = audioContext.createBuffer(numChannels, duration, sampleRate);
    var channelData = buffer.getChannelData(0);
    for (var i = 0; i < sampleRate; i++) {
      channelData[i]=Math.sin(2*Math.PI*frequency*i/(sampleRate));
    }
    var source = audioContext.createBufferSource();
    source.buffer = buffer;
    source.connect(audioContext.destination);
    source.start(0);
}

var online = false;

var time = () => new Date().toLocaleDateString('en-UK',{hour:'numeric', minute:'numeric', second:'numeric'})


setInterval(()=>{
  const isTyping = !!document.querySelector('[title="typing…"]');
  const isOnline = !!document.querySelector('[title="online"]')
  const considerOnline = isOnline || isTyping
  if(considerOnline !== online){ 
    online = considerOnline;
    if(online){ console.log('is online!', time() ); play(210) }
    else{ console.log('is not online!', time() ) } 
  }
},1000)