后端，清单树结构模型问题

app/lib/ledger.js

@@ -157,6 +157,7 @@ class baseTree {
      * @returns {Array}
      */
     getPosterity (node) {
+        const self = this;
         let posterity;
         if (node.full_path !== '') {
             const reg = new RegExp('^' + node.full_path + '-');
@@ -167,7 +168,7 @@ class baseTree {
             posterity = this._recursiveGetPosterity(node);
         }
         posterity.sort(function (x, y) {
-            return self.getNodeIndex(x) - self.getNodeIndex(y);
+            return self.getNodeSerialNo(x) - self.getNodeSerialNo(y);
         });
         return posterity;
     };