isAutoplaySupported.js

const isAutoplaySupported = function (callback) {
  var timeout;
  var waitTime = 200;
  var retries = 5;
  var currentTry = 0;
  var elem = document.createElement('video');
  var elemStyle = elem.style;

  function testAutoplay(arg) {
    currentTry++;
    clearTimeout(timeout);

    var result = arg && arg.type === 'playing' || elem.currentTime !== 0;

    if (!result && currentTry < retries) {
      //Detection can be flaky if the browser is slow, so lets retry in a little bit
      timeout = setTimeout(testAutoplay, waitTime);
      return;
    }

    elem.removeEventListener('playing', testAutoplay, false);
    callback(result);

    // Cleanup, but don't assume elem is still in the page -
    // an extension (eg Flashblock) may already have removed it.
    if (elem.parentNode) {
      elem.parentNode.removeChild(elem);
    }
  }

  //skip the test if video itself, or the autoplay
  //element on it isn't supported
  if (!(elem.canPlayType && elem.canPlayType('video/mp4; codecs="avc1.42E01E"').replace(/^no$/, '')) || !('autoplay' in elem)) {
    callback(false);
    return;
  }

  elemStyle.position = 'absolute';
  elemStyle.height = 0;
  elemStyle.width = 0;

  try {
    elem.src = 'data:video/mp4;base64,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';
  }

  catch (e) {
    callback(false);
    return;
  }

  elem.setAttribute('muted', '');
  elem.setAttribute('autoplay', '');
  elem.setAttribute('playsinline', '');
  elem.style.cssText = 'display:none';
  document.documentElement.appendChild(elem);
  // wait for the next tick to add the listener, otherwise the element may
  // not have time to play in high load situations (e.g. the test suite)
  setTimeout(function() {
    elem.addEventListener('playing', testAutoplay, false);
    timeout = setTimeout(testAutoplay, waitTime);
    try { elem.play() } catch (e) {}
  }, 0);
};

module.exports = isAutoplaySupported