code: function (height, width) {
          if (u.hasClass(this.element, 'u-menu-unaligned')) {
              // Do not clip.
              this.element.style.clip = '';
          } else if (u.hasClass(this.element, 'u-menu-bottom-right')) {
              // Clip to the top right corner of the menu.
              this.element.style.clip =
                  'rect(0 ' + width + 'px ' + '0 ' + width + 'px)';
          } else if (u.hasClass(this.element, 'u-menu-top-left')) {
              // Clip to the bottom left corner of the menu.
              this.element.style.clip =
                  'rect(' + height + 'px 0 ' + height + 'px 0)';
          } else if (u.hasClass(this.element, 'u-menu-top-right')) {
              // Clip to the bottom right corner of the menu.
              this.element.style.clip = 'rect(' + height + 'px ' + width + 'px ' +
                  height + 'px ' + width + 'px)';
          } else {
              // Default: do not clip (same as clipping to the top left corner).
              this.element.style.clip = 'rect(' + 0 + 'px ' + 0 + 'px ' +
                  0 + 'px ' + 0 + 'px)';
          }
      }
docs: Calculates the initial clip (for opening the menu) or final clip (for closing
  it), and applies it. This allows us to animate from or to the correct point,
  that is, the point it's aligned to in the "for" element.
  
  @param {number} height Height of the clip rectangle
  @param {number} width Width of the clip rectangle
  @private