[slrz]

Seems reasonable to me: this way, you don't have to duplicate the BOM stripping in the decoders of every single format you want to support.

It's also more general as there are other commonly-needed transformations that have an even weaker case for explicit support in the CSV library (charset conversion, dropping other bogus bytes, ...).

[maerF0x0]

it's a stark difference compared to, say, https://www.papaparse.com/ in javascript which pretty much does anything it can to parse a file