346     var delta = direction == 'prev' ? -1 : 1
347     var itemIndex = (activeIndex + delta) % this.$items.length
1464     var delta = this.getViewportAdjustedDelta(placement, offset, actualWidth, actualHeight)
1466     if (delta.left) offset.left += delta.left
1467     else offset.top += delta.top
1470 …var arrowDelta          = isVertical ? delta.left * 2 - width + actualWidth : delta.top * 2 - heig…
1477   Tooltip.prototype.replaceArrow = function (delta, dimension, isHorizontal) {  argument
1479       .css(isHorizontal ? 'left' : 'top', 50 * (1 - delta / dimension) + '%')
1559     var delta = { top: 0, left: 0 }  class in Tooltip.getViewportAdjustedDelta
1560     if (!this.$viewport) return delta
1569         delta.top = viewportDimensions.top - topEdgeOffset
1571         delta.top = viewportDimensions.top + viewportDimensions.height - bottomEdgeOffset
1577         delta.left = viewportDimensions.left - leftEdgeOffset
1579         delta.left = viewportDimensions.left + viewportDimensions.width - rightEdgeOffset
1583     return delta