property nextResource

This property returns the next resource in the library. firstResource should always be called first. See firstResource property for more information.

var lib = scene.importLibrary("box://app/theme/goldTheme.box");
if (lib)
{
    var res = lib.firstResource;
    while (res)
    {
        shell.print("Resource ID: " + res.id);
        res = lib.nextResource;
    }
}