jQuery by default defines “$” to be the jQuery function/object.
As you can see in the code that you excerpted, you appear to be calling go.GraphObject.make when you call “$”. So presumably you have some jQuery usage in the scope of your definition of “$”.
Unlike jQuery, GoJS does not presume to appropriate such a convenient short name. This allows us to coexist with every other library. You can either use “$” to refer to jQuery or go.GraphObject.make, but not both in the same scope. So either use a different variable name for go.GraphObject.make, or avoid jQuery’s use of “$” by calling jQuery.noConflict().