chore(protractor): speed up calls to then/each/map/reduce

Author: hankduan

Diff for: lib/protractor.js

@@ -261,7 +261,9 @@ var buildElementHelper = function(ptor) {
       return self.getWebElements().then(function(parentWebElements) {
         var list = [];
         parentWebElements.forEach(function(parentWebElement, index) {
-          var elementFinder = self.get(index); // Wrap in ElementFinder
+          var elementFinder = 
+              ElementFinder.fromWebElement_(parentWebElement, self.locator_);
+
           var filterResults = filterFn(elementFinder, index);
           if (filterResults instanceof webdriver.promise.Promise) {
             filterResults.then(function(satisfies) {
@@ -460,8 +462,8 @@ var buildElementHelper = function(ptor) {
     var self = this; 
     return this.getWebElements().then(function(arr) {
       var list = [];
-      arr.forEach(function(webElem, index) {
-        list.push(self.get(index));
+      arr.forEach(function(webElem) {
+        list.push(ElementFinder.fromWebElement_(webElem, self.locator_));
       });
       return list; 
     });
@@ -737,6 +739,14 @@ var buildElementHelper = function(ptor) {
   };
   util.inherits(ElementFinder, webdriver.promise.Promise);
 
+
+  ElementFinder.fromWebElement_ = function(webElem, locator) {
+    var getWebElements = function() {
+      return webdriver.promise.fulfilled([webElem]);
+    };
+    return new ElementArrayFinder(getWebElements, locator).toElementFinder_();
+  };
+
   /**
    * Create a shallow copy of ElementFinder.
    *