detect emoji support

emojid.js

var emojiSupported = (function() {
  var node = document.createElement('canvas');
  if (!node.getContext || !node.getContext('2d') ||
      typeof node.getContext('2d').fillText !== 'function')
    return false;
  var ctx = node.getContext('2d');
  ctx.textBaseline = 'top';
  ctx.font = '32px Arial';
  ctx.fillText('\ud83d\ude03', 0, 0);
  return ctx.getImageData(16, 16, 1, 1).data[0] !== 0;
})();