You can use the DSL IDE plugin to debug javascript in a job or job step context. This method lets you evaluate the javascript block easily in a clean interface, without having to re-run a procedure over and over again or do things in command line.
From your CloudBees CD (CloudBees Flow) UI, navigate to the DSL IDE tab and enter your javascript in the following format:
expandString jobStepId: '0b67ac38-2c57-11e7-8c23-de3220524153',
value: '''
$[/javascript myJob.outcome]
'''
Once you submit the DSL, the response will return with what the javascript evaluates to.
