Commander.js: When providing custom function for options, requiredOption don't work

[gitoutthere]

When:

  .requiredOption('--package-id <value>', 'The package identifier.', isAllowedValue, ['test1','test2','test3'])

Commander not existing asking for required option.

[shadowspawn]

Based on the code fragment you supplied, I expect Commander does not complain about the requiredOption because the option has a value.

const program = require('commander');

function isAllowedValue() {}

program
  .requiredOption('--package-id <value>', 'The package identifier.', isAllowedValue, ['test1','test2','test3']);

program.parse(process.argv);
console.log(program.packageId);

$ node index.js
[ 'test1', 'test2', 'test3' ]

[shadowspawn]

In particular, it is supplying the default value that means requiredOption does not complain. Not the addition of a custom function.

[gitoutthere]

So it is by design by the looks of it. Although I think reverse of that also make sense, requiredOption takes priority of default value provided.

How would you achieve what I want to achieve more elegantly?

[shadowspawn]

Yes it is by design. I like some patterns this allows like supplying a default value from an environment variable which may or may not be defined.

How would you achieve what I want to achieve more elegantly?

What do you want? (What does isAllowedValue have in it?)

[gitoutthere]

What do you want? (What does isAllowedValue have in it?)

It ensures the value provided is from a defined set of values. Also respect if that options is required or not.

  .requiredOption('--package-id <value>', 'The package identifier.', isAllowedValue, ['test1','test2','test3'])

In above example 'isAllowedValue' will exit if is not any of ['test1','test2','test3']. Even having ability to validate based on a regex. Just a thought.

[shadowspawn]

The open issue for exactly what you want is #518

(There actually is support to validate using a regular expression! But it is deprecated because it just silently returns default value for mismatches so disappointing in practice.)

I have been thinking about #518 and will add a possible implementation for supplying your own isAllowedValue.

[shadowspawn]

A possible minimal implementation.

function isAllowedValue(allowedValues) {
  // return a function which checks the value is in the allowedValues
  return (value) => {
    if (!allowedValues.includes(value)) {
      throw Error(`Invalid option value: ${value}`);
    }
    return value;
  }
}

program
  .requiredOption('--package-id <value>', 'The package identifier.', isAllowedValue(['test1','test2','test3']));

$ node index.js                   
error: required option '--package-id <value>' not specified
$ node index.js --package-id test1
test1
$ node index.js --package-id test4
/Users/john/Documents/Sandpits/commander/issues/1130/index.js:6
      throw Error('Invalid value for option');
      ^
...

[gitoutthere]

I did not see that being possible. Using same mechanism we do regex like:

function isAllowedValue(regExpStr) {
  // return a function which checks the value is in the allowedValues
  return (value) => {
    if (!RegExp(regExpStr).test(value)) {
      throw Error(`Invalid option value: ${value}`);
    }
    return value;
  }
}

program
  .requiredOption('--package-id <value>', 'The package identifier.', isAllowedValue('^(test1|test2|test3)$'));

[shadowspawn]

An answer was provided, and no further activity in a month. Closing this as resolved.

Feel free to open a new issue if it comes up again, with new information and renewed interest.