Coalescing on a field value that is pulled by onBefore Transform map (no field mapping) - Possible?

[KirthikaD]

Can a coalesce be set on a target record field which has no field mapping on the transform map, but value is scripted to it using on before transform script in servicenow?

We have a transform map that has 5 out of 8 field mappings coalesced. 

There is one target field, "Parent", which will not be populated on the xlsx file, but the value for this field is scripted using an onBefore Transform script.

Is there a way we can add a coalesce to this parent field, in addition to the existing coalesces?

[Mark Manders · Accepted solution]

The coalesce is set on the fields, so if you aren't mapping it, you can't put a coalesce on it.