gistfile1.txt

        onRouteChanged: function() {
          console.log(this.route)
          
          switch (this.route.page) {
            case "list":
              this.ensureUpgraded(this.$['shopping-list']);
              break;
            case "home":
              break;
            default:
              this.async(() => window.location.hash = '!/home');
              return;
          }

          var drawerPanel = document.querySelector('#paperDrawerPanel');
          if (drawerPanel.narrow) {
            drawerPanel.closeDrawer();
          }
        },

        ensureUpgraded: function(elem) {
          return new Promise((resolve, reject) => {
            if (Polymer.isInstance(elem)) {
              resolve();
            }
            
            let name = elem.nodeName.toLowerCase();
            console.log(name);
            console.log(`elements/${name}/${name}.html`);
            Polymer.Base.importHref(`elements/${name}/${name}.html`,
              () => resolve,
              () => reject);
          });
        },