Currently, since sub-formulas are not instantiated like formulas, they do not produce execution logs. However, since a sub-formula is also a formula step, the result of that sub-formula is represented in the steps object of the parent formula
If you're receiving a specific error, it should correlate to an individual step. For example, if you receive the following error: "Cannot read property 'Example' of undefined", then you know that there is something wrong with the Example
object. You should make sure that you are giving your objects and properties unique names that correlate to the specific step they're in. This setup will help you understand where the error is.
Generally speaking, it's likely that if a step fails, then it's the last one run for the sub-formula and therefore you should see it as the results of the formula step.
Finally, the best way to debug a sub-formula is to pass the `steps` object into your done() function. This will give you visibility into which steps have executed up to the point where the sub-formula completes or returns an error.