Unify isArray/isFunction/toString implementations

Restores Array.isArray polyfill for all use cases.

Fixes #645

lib/handlebars/base.js

@@ -12,25 +12,11 @@ export var REVISION_CHANGES = {
   4: '>= 1.0.0'
 };
 
-var toString = Object.prototype.toString,
+var isArray = Utils.isArray,
+    isFunction = Utils.isFunction,
+    toString = Utils.toString,
     objectType = '[object Object]';
 
-// Sourced from lodash
-// https://github.com/bestiejs/lodash/blob/master/LICENSE.txt
-var isFunction = function(value) {
-  return typeof value === 'function';
-};
-// fallback for older versions of Chrome and Safari
-if (isFunction(/x/)) {
-  isFunction = function(value) {
-    return typeof value === 'function' && toString.call(value) === '[object Function]';
-  };
-}
-
-function isArray(value) {
-  return (value && typeof value === 'object') ? toString.call(value) === '[object Array]' : false;
-}
-
 export function HandlebarsEnvironment(helpers, partials) {
   this.helpers = helpers || {};
   this.partials = partials || {};

lib/handlebars/utils.js

@@ -1,7 +1,5 @@
 import SafeString from "./safe-string";
 
-var isArray = Array.isArray;
-
 var escape = {
   "&": "&",
   "<": "&lt;",
@@ -26,6 +24,26 @@ export function extend(obj, value) {
   }
 }
 
+export var toString = Object.prototype.toString;
+
+// Sourced from lodash
+// https://github.com/bestiejs/lodash/blob/master/LICENSE.txt
+var isFunction = function(value) {
+  return typeof value === 'function';
+};
+// fallback for older versions of Chrome and Safari
+if (isFunction(/x/)) {
+  isFunction = function(value) {
+    return typeof value === 'function' && toString.call(value) === '[object Function]';
+  };
+}
+export var isFunction;
+
+export var isArray = Array.isArray || function(value) {
+  return (value && typeof value === 'object') ? toString.call(value) === '[object Array]' : false;
+};
+
+
 export function escapeExpression(string) {
   // don't escape SafeStrings, since they're already safe
   if (string instanceof SafeString) {