This post introduces Optique, a new library created to address the pervasive problem of repetitive and often messy validation code in CLI tools. The author was motivated by the observation that nearly every CLI tool reinvents the wheel with similar validation patterns for dependent options, mutually exclusive options, and environment-specific requirements. Optique leverages parser combinators and TypeScript's type inference to ensure that CLI arguments are parsed directly into valid configurations, eliminating the need for manual validation. By describing the desired CLI configuration with Optique, TypeScript automatically infers the types and constraints, catching potential bugs at compile time. The author shares their experience of deleting large chunks of validation code and simplifying refactoring tasks. Optique aims to provide a more robust and maintainable approach to CLI argument parsing, potentially saving developers from writing the same validation logic repeatedly.
I’ve used the node.js version of argparse, which as I understand it, is a clone of the python implementation and I’ve not seen how to do mutually exclusive flags. Mind you, at the time I didn’t need them, so it wasn’t an issue, but I don’t recall seeing any way to do it either.
Did I miss something?
https://docs.python.org/3/library/argparse.html#argparse.ArgumentParser.add_mutually_exclusive_group
However I’ve never had to use that feature. Like I said it can make sense in specific contexts but it is a pretty strong indicator that you have built in a CLI antipattern or too much complexity.