code: function() {
              var findShape = this.kityEvent && this.kityEvent.targetShape;
              if (!findShape) return null;
              while (!findShape.minderNode && findShape.container) {
                  findShape = findShape.container;
              }
              var node = findShape.minderNode;
              if (node && findShape.getOpacity() < 1) return null;
              return node || null;
          }
docs: @method getTargetNode()
  @for MinderEvent
  @description 当发生的事件是鼠标事件时，获取事件位置命中的脑图节点
  
  @grammar getTargetNode() => {MinderNode}