isFalsy is just “!”; I don't think we need a new library for a more verbose way to express a one-character unary operator, no, nor does it meet the standard of “The problem it solves is not straightforward” proposed upthread.
I'm not surprised it exists (and literally is just a more verbose, indirect way to invoke “!” that nevertheless is a 17 sloc module with a bunch of ancillary files that has one direct and, by way of that one, 17 second-order and, while I didn't check further, probably an even more ridiculous number of more distant, transitive dependendencies.)
I'm just saying it's neither necessary nor consistent with the standard for when a library is a good idea proposed upthread, so suggesting it as part of an attempt at reductio as absurdam on that standard is misplaced.
