How to read on screen field values in Forge Workflow Validator


We are trying to implement a workflow validator through Forge.
We have the following fields in Jira issue close screen:
“Resolution” - Done, Won’t implement, Duplicate
“Release Version” - It is a version picker

We want to add validator in the close screen as follow:
If Done option is selected in “Resolution” field, then “Release Version” field is required

Please help in fetching onscreen field values in Forge validator

Thank you.