faster iteration with static __stepNext method

README.md

@@ -550,14 +550,11 @@ emitter, and the visitor is not called on them.  The emitter does not throw, un-
 errors are ignored.  Errors accessing the top-level `dirname` are returned to the callback.
 
 
-Traverse the directory
-
-
 Changelog
 ---------
 
 - 1.8.0 - new `makeError`, `compileVinterpolate`, `microtime`, `repeatFor`, `pairTo`, document repeatUntil, walkdir,
-          fix getProperty() for un-dotted names longer than 40 chars, faster getProperty
+          fix getProperty() for un-dotted names longer than 40 chars, faster getProperty, faster iteration
 - 1.7.3 - new undocumented `repeatUntil`, `walkdir`
 - 1.7.2 - fix escaped \] in globRegex char lists [...]
 - 1.7.1 - new function `globRegex`

qibl.js

@@ -924,20 +924,22 @@ function sortBy( items, getMetric ) {
 // iterator() returns a traversal object with a method next().
 // next() returns a data wrapper with properties {value, done}.
 // If done is set then value is not to be used.
+//
+// __stepNext is 25% faster if static and reused (walking 10 items; 70% for 40)
+function __stepNext() { this.__step(this.__state, this.__instance, this); return this; }
 function makeIterator( step, makeState ) {
     return function qiblIterator() {
         // makeState is passed the object instance on which the iterator was called
         var state = makeState && makeState(this) || {};
         return {
             value: 0,
             done: false,
-            next: stepIterator,
+            next: __stepNext,
             __step: step,
             __state: state,
             __instance: this,
         };
     }
-    function stepIterator() { this.__step(this.__state, this.__instance, this); return this; }
 }
 // install the iterator as Symbol.iterator if the node version supports symbols, else as ._iterator
 function setIterator( obj, iterator ) {