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

1 files changed, 5 insertions, 2 deletions

diff --git a/lib/handlebars/base.js b/lib/handlebars/base.js
index a1b3461..dcf446b 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) {