Dash inside option name with parser option strip-dashed yields undefined value

[koraa]

This is a bug report; minimal example of the bug:

$ node -e "console.log(require('yargs').parserConfiguration({ 'strip-dashed': true}).option('foo-bar', { coerce: (v) => v }).parse(['executable', '--foo-bar', 'hello']))"

outputs:

{
  _: [ 'executable' ],
  fooBar: undefined,
  '$0': '',
  'foo-bar': undefined
}

This is incorrect. The value of 'fooBar' should be 'hello', not undefined and the 'foo-bar' property should be entirely removed.

This bug does not appear with options not containing a dash:

node -e "console.log(require('yargs').parserConfiguration({ 'strip-dashed': true}).option('foobar', { coerce: (v) => v }).parse(['executable', '--foobar', 'hello']))"

yields the following correct output:

{ _: [ 'executable' ], foobar: 'hello', '$0': '' }

Workaround No 1

Setting 'strip-dashed' to false yields correct behaviour:

node -e "console.log(require('yargs').parserConfiguration({ 'strip-dashed': false }).option('foo-bar', { coerce: (v) => v }).parse(['executable', '--foo-bar', 'hello']))"

resulting js:

{ _: [ 'executable' ], 'foo-bar': 'hello', fooBar: 'hello', '$0': '' }

Woraround No 2

Using an alias also yields less wrong behavior (still no stripping).

node -e "console.log(require('yargs').parserConfiguration({ 'strip-dashed': true}).option('foobar', { alias: ['foo-bar'], coerce: (v) => v }).parse(['executable', '--foo-bar', 'hello']))"

Output:

{
  _: [ 'executable' ],
  foobar: 'hello',
  fooBar: 'hello',
  '$0': '',
  'foo-bar': 'hello'
}

[bcoe]

@koraa thank you for the bug report. I went ahead and transferred this over to yargs-parser, which is potentially where the bug will need to be fixed.

Although, the fact that coerce is now handled in yargs means you it could also be an issue there 🤔

[marikaner]

I just noticed a similar (probably the same) bug: I have options that are paths (e.g. outputDir), I used a parser config:

    .parserConfiguration({
      'strip-aliased': true,
      'strip-dashed': true
    })

and configured the path options with normalize. With this combination I always get output-dir and o (alias) in the parsed object.

[shadowspawn]

Thanks for the report. I recently looked into some related issues in yargs@17.x and opened a PR to (hopefully) fix the interaction of coerce and non-default configuration settings. I am confident enough that this will fix the issues, I'll move this issue back to yargs!

#2308

[shadowspawn]

Clever having the reproduction on the command-line. The behaviour has changed in current yargs version, but still broken as coerce is not run:

% node -e "console.log(require('yargs').parserConfiguration({ 'strip-dashed': true}).option('foo-bar', { coerce: (v) => v.toUpperCase() }).parse(['executable', '--foo-bar', 'hello']))"

{ _: [ 'executable' ], fooBar: 'hello', '$0': '' }

Running against #2308 code:

% node -e "console.log(require('yargs').parserConfiguration({ 'strip-dashed': true}).option('foo-bar', { coerce: (v) => v.toUpperCase() }).parse(['executable', '--foo-bar', 'hello']))"

{ _: [ 'executable' ], fooBar: 'HELLO', '$0': '' }