I don't see anything wrong with using a pre-made left pad function. Why waste time and lines of code implementing something so trivial when there is already a solution available? However, I agree it is ridiculous to have a dedicated module for that one function. For most nontrivial projects I just include lodash, which contains tons and tons of handy utility functions that save time and provide efficient, fast implem…
(And, y'know, maybe it's because I'm not a JS programmer, but the notion of looking for a module to implement a string padding function would never have even occurred to me.)