Adding .choices(['a', 'b', 'c]) to a variadic option removes its variadic-ness

[MikeyBurkman]

Version: 7.0.0

I was super happy about the recent addition of choices() to options, but when I add choices to a variadic option, the option changes to a single value:

program
  .command('services')
  .addOption(
    new Option(
      '-e, --env <names...>',
      'The environment(s) to look up'
    ).choices(['dev', 'stg', 'prod'])
  )
  .action((args) => console.log(args));

foo services -e dev -e stg

Without .choices(), env becomes an array of ['dev', 'stg']. However, after adding choices, it becomes a single value 'stg'.

[shadowspawn]

Short version: yes, this is currently a known limitation.

Long version

I had realised there were some limitations like this when adding the variadic support.

.choices() is implemented the same way as custom option processing functions supplied by the user. Commander does not know whether a custom function is a simple coercion (like .choices()) or a complex function that accumulates values. All variadic does when there is a custom function is call it multiple times and leaves it up to the custom function to decide what to return. This works fairly well with the complex custom functions but not much use with the simple coerce functions!

To get .choices() working with variadic we can either extend the choices implementation to understand about variadic, or add a way to tell apart simple and complex custom option processing functions. (I like the second way as a general solution, but possibly too complex. Say adding .coerce() on Option to use for adding simple custom functions. Perhaps easier to support variadic inside choices.)

[shadowspawn]

.choices() now plays well with variadic from Commander 7.1.0