code: function () {
        if (!els.length) return
        els.forEach(function(el, key) {
          if (diffEls[key] && !diffEls[key].isEqualNode(el)) {
            el.parentElement.replaceChild(diffEls[key], els[key])
            els.splice(key, 1, diffEls[key])
            return
          }
        })
        diffEls = []
      }
docs: Update Element