I, like many other people, also took a stab at my ORM / ActiveRecord lib (First for PHP on MySQL, later ported it to Javascript on WebSQL) and I've been following exactly the sentiment that a people here seem to have to: Don't make your ORM want to do everything. If you are going to need computed N+1 queries, write a View, or use custom SQL.
ORM / ActiveRecord is a great pattern imo, but if you want to make it do everything, like so many other techniques, you're gonna end up with a behemoth of a thing.
I've tried many different ORMs in the last couple of years, and while mine may not be the most complete or have a sexy API for joining custom query parameters into the results, I still feel my own provides the one and only syntax / workflow 'as it should be' in Javascript:
var serie = new Serie();
serie.name = 'Arrow';
serie.TVDB_ID = '257655';
serie.Persist().then(function(result) {
console.log("Serie persisted! ", result);
});
I've got loads of examples with jsfiddles if you want to find out more :-)
https://github.com/SchizoDuckie/CreateReadUpdateDelete.js
(browser that supports WebSQL required, obviously)