Screen recorder in JS

canvasrecord.js

let canvas = document.querySelector('canvas');
// Optional frames per second argument.
let stream = canvas.captureStream(25);
let recorder = new MediaRecorder(stream, options);
let blobs = [];

function download(blob) {
  var url = window.URL.createObjectURL(blob);
  var a = document.createElement('a');
  a.style.display = 'none';
  a.href = url;
  a.download = 'test.webm';
  document.body.appendChild(a);
  a.click();
  setTimeout(function() {
    document.body.removeChild(a);
    window.URL.revokeObjectURL(url);
  }, 100);
}

recorder.ondataavailable = e => { console.log(e.data); if (e.data && e.data.size > 0) blobs.push(e.data)};
recorder.onstop = (e) => download(new Blob(blobs, , {type: 'video/webm'}));

recorder.start(10); // collect 10ms of data

setTimeout(()=> recorder.stop(), 10000);