lib/utils.js
function filterOutMetaWithId(metas) {
  metas = Array.prototype.slice.call(metas || []);
  return metas.filter(function (meta) {
    return !meta.id;
  });
}
function filterOutMetaWithId(metas) {
  metas = Array.prototype.slice.call(metas || []);
  return metas.filter(function (meta) {
    return !meta.id;
  });
}
Note:
1. In server side we will add meta tags and title at last after fitering
2. In client we will match and replace meta tagString
3. For now we will not support link and other tags properly, they can be added but we will not check for uniqueness and will not decide placement