Ensure that programs always return strings

Fixes #1838

lib/handlebars/compiler/javascript-compiler.js

@@ -308,7 +308,7 @@ JavaScriptCompiler.prototype = {
 
     if (appendOnly) {
       if (bufferStart) {
-        bufferStart.prepend('return ');
+        bufferStart.prepend('return "" + ');
         bufferEnd.add(';');
       } else if (!sourceSeen) {
         this.source.push('return "";');

spec/javascript-compiler.js

@@ -34,6 +34,7 @@ describe('javascript-compiler api', function() {
         .toCompileTo('food');
     });
   });
+
   describe('#compilerInfo', function() {
     var $superCheck, $superInfo;
     beforeEach(function() {
@@ -58,6 +59,7 @@ describe('javascript-compiler api', function() {
         .toCompileTo('food ');
     });
   });
+
   describe('buffer', function() {
     var $superAppend, $superCreate;
     beforeEach(function() {
@@ -116,4 +118,23 @@ describe('javascript-compiler api', function() {
       });
     });
   });
+
+  describe('options', function() {
+    it('should append `noEscape` statements as string', function() {
+      expectTemplate('{{a}}{{b}}')
+        .withCompileOptions({ noEscape: true })
+        .withInput({ a: 1, b: 1 })
+        .toCompileTo('11');
+    });
+
+    it('should append `noEscape` statements as string in a block', function() {
+      expectTemplate('{{#block}}{{a}}{{b}}{{/block}}')
+        .withCompileOptions({ noEscape: true })
+        .withHelper('block', function(options) {
+          return options.fn(this);
+        })
+        .withInput({ a: 1, b: 1 })
+        .toCompileTo('11');
+    });
+  });
 });