Imported scripts can't reference each other

If I have a QML file like:

import Qt 4.7
import "a.js" as A
import "b.js" as B
Item {
}

and a.js looks like:

.pragma library
var foo = "foo";

and b.js looks like:

.pragma library
console.log(foo);

I get undefined printed from b.js when running the QML file. By changing b.js to:

.pragma library
console.log(A.foo);

I get:

TypeError: Result of expression 'A' [undefined] is not an object.

I would expect that there would be some way for imported JS files to reference each other.