code: function() {
          if (this.loaded >= this.items.length) {
              this.shutdown();
              return;
          }
  
          this.fireEvent('loading');
  
          this.items.each(function(index, item) {
              if (item && this.inViewport(item)) {
                  this.show(item, index);
              }
          }.bind(this));
  
          this.fireEvent('loaded');
      }
docs: Loop over the lazy loaded items and verify they are within the viewport.