Prevent Sub-task Creation in Jira Cloud

Preventing users from creating subtasks when the parent is of a certain type.

Jira Expression

The Jira Expression below does two things. The first part checks if the issue to be created has a parent. This is to allow issue creation of issues without a parent (that is, a standard Jira issue).

The second part (separated by the OR operator "||") is to define the issue type of the parent. If the subtask being created has a parent of (in the case of this example, issue type "Task" or "Story"), users will not be able to create subtasks.

issue.parent == null || ['Task', 'Story'].includes(issue.parent.issueType.name)