dominictarr/relational-join-stream — pull request #1 by mcollina (2013-05-01 20:00:58+00:00)
Title: No emit on undefined.

I think that the `reduce` function might be allowed to 'drop' some results.
If it returns `undefined`, then it will not emit `data`.

I do not know how to test it within the test system, but it works.