Use optional argument in memoize-util benchmark

perf/benchmarks/memoize-util/index.js

@@ -3,7 +3,7 @@ const { default: memoize } = require('../../../lib/utils/memoize')
 module.exports = {
   setup(state) {
     let obj = {
-      fibonacci(n) {
+      fibonacci(n = 20) {
         if (n === 0 || n === 1) {
           return n
         } else {
@@ -17,6 +17,6 @@ module.exports = {
   },
 
   run(obj) {
-    obj.fibonacci(20)
+    obj.fibonacci()
   }
 }

src/models/node.js

@@ -179,6 +179,7 @@ const Node = {
 
   /**
    * Recursively filter all descendant nodes with `iterator`, depth-first.
+   * It is different from `filterDescendants` in regard of the order of results.
    *
    * @param {Function} iterator
    * @return {List} nodes