underscore mixin to mutate html containing youtube or vimeo video url's to embed html

video.js

_.mixin({
  mutateVideoUrlsToEmbeds: function(html) {
    let embed = '';
    const youtubeRegEx = /(?:http?s?:\/\/)?(?:www\.)?(?:youtu\.be|youtube\.com)\/(?:embed\/|v\/|watch\?v=|watch\?.+&v=)?((\w|-){11})/g;
    const vimeoRegEx = /(?:http?s?:\/\/)?(?:www\.)?(?:vimeo\.com)\/(.*)/g;

    if (youtubeRegEx.test(html)) {
      embed = '<iframe width="360" height="270" src="//www.youtube.com/embed/$1" frameborder="0" allowfullscreen></iframe>';
      html = html.replace(youtubeRegEx, embed);
    }

    if (vimeoRegEx.test(html)) {
      embed = '<iframe width="360" height="270" src="//player.vimeo.com/video/$1" frameborder="0" allowfullscreen></iframe>';
      html = html.replace(vimeoRegEx, embed);
    }

    return html;
  }
});