I've created a new Site Collection, and am building a List with a User field on it.
When I manually add items to that list, it lets me search for all the users in my Active Directory, even if they're not in the UserInformationList. Though I see that after I add them to a List Item, they do show up there. And the value stored in that User field is their ID on the UserInformationList.
So how do I add users, that I get from with JSOM and the REST API, to a User field, also using JSOM and the REST API?