example.js

var self = this;
var uglyVm = {
  object1 : ko.observable("hello there"),
  object2 : ko.observable(new (function () {
    var self = this;
    
    self.subObject1 = ko.observable("goodbye now");
  })(self))
};


//should also work the same as this (relatively)
var simpleVm = {
  object1 : ko.observable("hello there"),
  object2 : {
    subObject1 : ko.observable("goodbye now")
  }
};


//another way, to seperate them out even farther
//create the subVm seperate, probably as a function returning an object
//with a constructor to just pass your values in
//like:
// new subVm(item1, item2, addressId, "some other property");
var subVm = {
  subObject1 : ko.observable("goodbye now")
};

var simplarVm = {
  object1: ko.observable("hello there"),
  object2: new subVm(/*with arguments of what you needed to fill at runtime */))
};