How to fetch encapsulated reference field's parent object

Let’s say I have a type like:
type A {
b: B
c: string
}

and type is defined like:
type B {
d: int
someMethod: function(): string
}

Is there a way for me to know what’s contained in field c of an object of type A during the run time, form within the implementation of someMethod? Something like this.parent.c (assuming the parent field gives me the specific object instance of type A)

types A and B are non persistable.

you don;t have parent on type B, unless you define it and set it explicitly. Depending how you set it you may have access or not to field c. e.g.

var a = A.make({c: 'this is c'});
var b = B.make({parent: A}); // at this moment you should have something under `someMethod ` for `this.parent.c`
a.b = b;