refact(ngOptions): clean up iterating over option values

Author: petebacondarwin

src/ng/directive/ngOptions.js

@@ -230,6 +230,17 @@ var NG_OPTIONS_REGEXP = /^\s*([\s\S]+?)(?:\s+as\s+([\s\S]+?))?(?:\s+group\s+by\s
 
 var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
 
+  function iterateOverObjectProperties(obj, fn) {
+    // extract keys, in enumeration order, unsorted
+    var keys = Object.keys(obj);
+    keys.forEach(function(key) {
+      if (key.charAt(0) !== '$') {
+        fn(obj[key], key);
+      }
+    });
+  }
+
+
   function parseOptionsExpression(optionsExp, selectElement, scope) {
 
     var match = optionsExp.match(NG_OPTIONS_REGEXP);
@@ -321,30 +332,11 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
 
         var optionItems = [];
         var selectValueMap = {};
-
-        // The option values were already computed in the `getWatchables` fn,
-        // which must have been called to trigger `getOptions`
         var optionValues = valuesFn(scope) || [];
-        var optionValuesKeys;
+        var forEachOptionValue = (!keyName && isArrayLike(optionValues)) ? forEach : iterateOverObjectProperties;
 
 
-        if (!keyName && isArrayLike(optionValues)) {
-          optionValuesKeys = optionValues;
-        } else {
-          // if object, extract keys, in enumeration order, unsorted
-          optionValuesKeys = [];
-          for (var itemKey in optionValues) {
-            if (optionValues.hasOwnProperty(itemKey) && itemKey.charAt(0) !== '$') {
-              optionValuesKeys.push(itemKey);
-            }
-          }
-        }
-
-        var optionValuesLength = optionValuesKeys.length;
-
-        for (var index = 0; index < optionValuesLength; index++) {
-          var key = (optionValues === optionValuesKeys) ? index : optionValuesKeys[index];
-          var value = optionValues[key];
+        forEachOptionValue(optionValues, function(value, key) {
           var locals = getLocals(value, key);
           var viewValue = viewValueFn(scope, locals);
           var selectValue = getTrackByValue(viewValue, locals);
@@ -355,7 +347,7 @@ var ngOptionsDirective = ['$compile', '$parse', function($compile, $parse) {
 
           optionItems.push(optionItem);
           selectValueMap[selectValue] = optionItem;
-        }
+        });
 
         return {
           items: optionItems,