From 84049bf0c5576727e9d6a0880abb123454d28861 Mon Sep 17 00:00:00 2001
From: kpdecker <kpdecker@gmail.com>
Date: Mon, 14 Oct 2013 21:36:46 -0500
Subject: [PATCH] Add includeZero flag to if conditional

Allows for users who desire non-falsy handling of numbers to utilize if while maintaining the legacy if behavior.

Fixes #608
---
 lib/handlebars/base.js | 7 +++++--
 spec/builtins.js       | 7 +++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/lib/handlebars/base.js b/lib/handlebars/base.js
index a1b346104..dcf446b78 100644
--- a/lib/handlebars/base.js
+++ b/lib/handlebars/base.js
@@ -133,7 +133,10 @@ function registerDefaultHelpers(instance) {
   instance.registerHelper('if', function(conditional, options) {
     if (isFunction(conditional)) { conditional = conditional.call(this); }
 
-    if (Utils.isEmpty(conditional)) {
+    // Default behavior is to render the positive path if the value is truthy and not empty.
+    // The `includeZero` option may be set to treat the condtional as purely not empty based on the
+    // behavior of isEmpty. Effectively this determines if 0 is handled by the positive path or negative.
+    if ((!options.hash.includeZero && !conditional) || Utils.isEmpty(conditional)) {
       return options.inverse(this);
     } else {
       return options.fn(this);
@@ -141,7 +144,7 @@ function registerDefaultHelpers(instance) {
   });
 
   instance.registerHelper('unless', function(conditional, options) {
-    return instance.helpers['if'].call(this, conditional, {fn: options.inverse, inverse: options.fn});
+    return instance.helpers['if'].call(this, conditional, {fn: options.inverse, inverse: options.fn, hash: options.hash});
   });
 
   instance.registerHelper('with', function(context, options) {
diff --git a/spec/builtins.js b/spec/builtins.js
index 140f5f510..401e789a9 100644
--- a/spec/builtins.js
+++ b/spec/builtins.js
@@ -15,8 +15,11 @@ describe('builtin helpers', function() {
                       "if with non-empty array shows the contents");
       shouldCompileTo(string, {goodbye: [], world: "world"}, "cruel world!",
                       "if with empty array does not show the contents");
-      shouldCompileTo(string, {goodbye: 0, world: "world"}, "GOODBYE cruel world!",
-                      "if with zero does show the contents");
+      shouldCompileTo(string, {goodbye: 0, world: "world"}, "cruel world!",
+                      "if with zero does not show the contents");
+      shouldCompileTo("{{#if goodbye includeZero=true}}GOODBYE {{/if}}cruel {{world}}!",
+                      {goodbye: 0, world: "world"}, "GOODBYE cruel world!",
+                      "if with zero does not show the contents");
     });
 
     it("if with function argument", function() {