Scripting in SCP Workflow Cloud Foundry

Hello,

I am manipulating data in a script task in SCP Workflow on Cloud Foundry.

I got object stored in the context

$.context.myObj = {
                    key1: val1,
                    key2: val2,
                    key3: val3
};

Now I try to handle that object as a standard JS object

Object.keys($.context.myObj).forEach(.....)

I got an error

TypeError: [object ContextObject] is not an Object in <eval> at line number 2

Where can I find the specification of that special kind of object and how to handle them? Is there some specification, documentation or at least some information (beside that standard docu)