Yep. "Passing a comment" is used by calling .toString() on the function. It fails when using minification for obvious reasons but of course you wouldn't on Node code.
It's a clever hack around JS's awful multiline string support. But with ES6 template strings it's not really needed anymore.
Every time I was reading about old COBOL systems, I was wondering if we can compile COBOL to asm.js, this is slightly other direction but IMHO this topic requires more love.
Seems like a pretty stupid way to do it. Why not just use the raw data from the data files or direct access to the DB/2 database? Does this even handle the ebcdic to ascii conversion? Or packed decimal numbers?