Use Snap Blocks through Javascript?

So, I was wondering. Can you use Snap Blocks through the Javascript block in Snap?

Yes, but it's complicated. At any moment the browser might switch from Snap! to another tab, and when it's our turn again it's lost the stack information. There's an invoke() function in our JS code, but it has a comment next to it that says "Don't try this at home."

Look at the definitions of the new HOF primitives, e.g., reportMap(), and do what they do, and cross your fingers.

Unless Jens is about to tell me that this caution is obsolete...