Provide the JSOM API to create SharePoint Site Collections (Tenant Object as CSOM C# has)
BTW - I would suggest to add a new category as "JSOM Gaps"
Thanks for your feedback! Although we appreciate your time and effort to give us this feedback, it’s not something we’re planning to do right now. We are looking into possibly opening up admin REST APIs in the future, but do not have exact timeline for this right now.