Gruntfile.js

@@ -167,8 +167,8 @@ module.exports = function(grunt) {
           browsers: [
             {browserName: 'chrome'},
             {browserName: 'firefox', platform: 'Linux'},
-            {browserName: 'safari', version: 9, platform: 'OS X 10.11'},
-            {browserName: 'safari', version: 8, platform: 'OS X 10.10'},
+            // {browserName: 'safari', version: 9, platform: 'OS X 10.11'},
+            // {browserName: 'safari', version: 8, platform: 'OS X 10.10'},
             {browserName: 'internet explorer', version: 11, platform: 'Windows 8.1'},
             {browserName: 'internet explorer', version: 10, platform: 'Windows 8'}
           ]
@@ -187,6 +187,14 @@ module.exports = function(grunt) {
       }
     },
 
+    bgShell: {
+      checkTypes: {
+        cmd: 'npm run checkTypes',
+        bg: false,
+        fail: true
+      }
+    },
+
     watch: {
       scripts: {
         options: {
@@ -202,6 +210,7 @@ module.exports = function(grunt) {
   // Build a new version of the library
   this.registerTask('build', 'Builds a distributable version of the current project', [
                     'eslint',
+                    'bgShell:checkTypes',
                     'parser',
                     'node',
                     'globals']);
@@ -222,6 +231,7 @@ module.exports = function(grunt) {
   grunt.loadNpmTasks('grunt-contrib-uglify');
   grunt.loadNpmTasks('grunt-contrib-watch');
   grunt.loadNpmTasks('grunt-babel');
+  grunt.loadNpmTasks('grunt-bg-shell');
   grunt.loadNpmTasks('grunt-eslint');
   grunt.loadNpmTasks('grunt-saucelabs');
   grunt.loadNpmTasks('grunt-webpack');

components/bower.json

@@ -1,6 +1,6 @@
 {
   "name": "handlebars",
-  "version": "4.1.1",
+  "version": "4.1.2",
   "main": "handlebars.js",
   "license": "MIT",
   "dependencies": {}

components/handlebars.js.nuspec

@@ -2,7 +2,7 @@
 <package>
 	<metadata>
 		<id>handlebars.js</id>
-		<version>4.1.1</version>
+		<version>4.1.2</version>
 		<authors>handlebars.js Authors</authors>
 		<licenseUrl>https://github.com/wycats/handlebars.js/blob/master/LICENSE</licenseUrl>
 		<projectUrl>https://github.com/wycats/handlebars.js/</projectUrl>

components/package.json

@@ -1,6 +1,6 @@
 {
   "name": "handlebars",
-  "version": "4.1.1",
+  "version": "4.1.2",
   "license": "MIT",
   "jspm": {
     "main": "handlebars",

lib/handlebars/base.js

@@ -4,7 +4,7 @@ import {registerDefaultHelpers} from './helpers';
 import {registerDefaultDecorators} from './decorators';
 import logger from './logger';
 
-export const VERSION = '4.1.1';
+export const VERSION = '4.1.2';
 export const COMPILER_REVISION = 7;
 
 export const REVISION_CHANGES = {

lib/handlebars/helpers/lookup.js

@@ -1,5 +1,11 @@
 export default function(instance) {
   instance.registerHelper('lookup', function(obj, field) {
-    return obj && obj[field];
+    if (!obj) {
+      return obj;
+    }
+    if (field === 'constructor' && !obj.propertyIsEnumerable(field)) {
+      return undefined;
+    }
+    return obj[field];
   });
 }