VerifyOntologyEdits in Typescript -- verifying against any string

Is it possible to to check that a property was edited (ie assigned to a string) but not actually check the equality of a string. I’m using an object as a log and I want to store the stack trace, so checking equality on that property is close to impossible. However, I do want to check no other edits are made (ie objects created) when errors are thrown.

 verifyOntologyEditFunction(() =>  class.processFunction(event))
                .modifiesObject({
                    object: event, 
                    properties: {
                        processedStatus: EventStatus.ErrorInProcessing
                    } 
                }).createsObject({
                    objectType: FunctionLog, 
                    properties: {
                        primaryKey_: uuid, 
                        title: `This is my nice title`,
                        message: "This is a long message",
                        functionName: "processFunction",
                        type: "ERROR",
                        sourceObjectRid: event.rid_,
                        timestamp: currentTime, 
                        // I want to check that stack is updated but not check equality 
                        stack: someString(), 
                    }
                })
                .hasNoMoreEdits();
    });