Add regex parameter to `.argument`

[MaxumCSmith]

I find myself having to validate arguments more thoroughly using Regex. I end up doing this from within the action method, but it would be nice if we could pass another parameter into .argument as a regex that would be used to validate.

Maybe something like this would be nice?

argument(name: string, description?: string, defaultValue?: unknown): this; -> argument(name: string, description?: string, defaultValue?: unknown, validationRegex: Regex): this;

[shadowspawn]

You can write a custom processing function that validates the argument with a regular expression.

See https://github.com/tj/commander.js#custom-argument-processing and have a look at myParseInt in the Custom option processing section

To avoid writing multiple parsers if you want to use different regex you can write a function to generate the parser from the regex, see later comments in #1130

[MaxumCSmith]

I see. I didn't notice the ability to pass in a processing function. fn should enable what I need.

• argument<T>(flags: string, description: string, fn: (value: string, previous: T) => T, defaultValue?: T): this;

Thank you.

[shadowspawn]

I'll close this issue, but #1909 is still open and flagged for reviewing the documentation.