Expected behavior for jsonpath in when clause if path is missing

[apiwoni]

What is expected behavior in when clause with

{{=jsonpath(tasks.TaskName.outputs.parameters.parameterName,'$.propertyName)}} != true

condition if the path does not exist, either no outputs or missing property?

It seems we get Invalid 'when' expression error.
Is there a way to test path existence if that's the case?
Is there a way to test for property existence at a given path?

[apiwoni]

I'm answering my question here but additional ideas and notes are welcome.

So yes, invalid 'when' expression also happens when actual path is missing for jsonpath.

Here's one way to handle it:

tasks.TaskName.outputs != nil && 
tasks.TaskName.outputs.parameters.parameterName != nil &&
tasks.TaskName.outputs.parameters.parameterName contains 'propertyName' &&
jsonpath(tasks.TaskName.outputs.parameters.parameterName, '$.propertyName') != 'true'

[agilgur5]

You can also use optional chaining with ?. to simplify the logic a bit