text: export default {
      setDepth(value) {
          this.depth = value;
          if (this.children) {
              var children = this.getAllChildren();
              for (var i = 0, cnt = children.length; i < cnt; i++) {
                  children[i].depth = value;
              }
          }
          return this;
      },
  
      swapDepth(containerB) {
          var depthA = this.depth;
          var depthB = containerB.depth;
          this.setDepth(depthB);
          containerB.setDepth(depthA);
          return this;
      },
  
      incDepth(inc) {
          this.depth += inc;
          if (this.children) {
              var children = this.getAllChildren();
              for (var i = 0, cnt = children.length; i < cnt; i++) {
                  children[i].depth += inc;
              }
          }
          return this;
      },
  };