Using handlebars with browserify causes IE to throw - TypeError: Invalid calling object 

The isEmpty function in lib/utils uses a cached pointer to Object.prototype.toString.  When a module is browserified, it is wrapped in a closure scope.  In IE, there is a scope conflict which causes the use of the cached toString function pointer to result in

TypeError: Invalid calling object

Adding local cached pointer to Object's toString method resolves the issue.

isEmpty is used in the if helper.