Numbered placeholder support is now available in a full release. There are tests and also examples in the docs which are automatically tested but it's possible there are edge-case bugs in this functionality since it is brand new. If you use Node.js and PostgreSQL (which requires numbered placeholders), I would really appreciate you testing this and reporting any bugs with repro cases as GH issues. Thank you!

This first version of numbered placeholders does not attempt to reuse duplicate values but that's something I might add in future, if folks think it's worth it?