It advertises 0 dependencies? Really? It's 86 lines of code and really boils down to 1: "return amount * getRate({base, rates, from, to});". A fucking multiplication. Who needs a library for this anyway? JavaScript and its ecosystem is a joke.
You're free to roll your own JS utility function that performs this multiplication.
Personally, I don't know why this is on HN as it's not an exceptional utility, and doesn't handle common currency manipulation frustrations (floating point rounding, bigint, decimal formatting, signs, etc.)