Hi,
I started reading the docs (https://developer.atlassian.com/) a few days ago and I see many samples with : JIRA.[something]
For exmaple:
JIRA.IssueNavigator.getSelectedIssueKey()
JIRA.Issue.getIssueKey()
JIRA.Messages.showWarningMsg('sample warning msg')
JIRA.CONTENT_ADDED_REASON.pageLoad
These samples are cutted part from code, so it doesn’t matters what it does, but they are very similliar to these which I saw in Scriptrunner when I worked with Groovy so they are attractive for me, but I really can’t find complete list/doc with this modules/packages (don’t know how to call this) and don’t want to guess, so anyone knows where can I find it?
My currently problem is check that logged user is in selected group so I hope it is possible to do with this tool
Except that (but it’s not necessery) if someone can recommend other good docs related to developing with atlassian product I will be very happy, because there are so many of them that you can get lost and I don’t know what to focus on 
Sample source:
https://developer.atlassian.com/server/jira/platform/extending-inline-edit-for-jira-plugins/
Thanks in advance