Not a Javascript library. The post advocates generators for Javascript programmers. For core.async to tell us the efficiency of JS code of this style, it'd need to expose a generator-based interface and compile to generator-based code like a human writes. If I understand right, it doesn't, and the JS libraries that do work this way are much less efficient when full stack traces are turned on. (If there are others, I hope someone will chime in.)

If you think those two libraries are just bad, I'll update somewhat in that direction.

No the post advocates generators plus a competent channel abstraction. It's going to be hard to compare generator libraries to core.async, far as I can tell none employ the comprehensive set of optimizations that we do for time and memory. Perhaps when someone ports our ideas to JavaScript a real comparison can be made.