Incompatible behaviour w/ Spectral in regards to casing function with a specific separator char

[bpaugam]

Bug

When using the casing function in validation rule, Spectral and Vacuum are not compatible with its functionOptions when specifying a separator character.

# Spectral
...
then:
  function: casing
  functionOptions: 
    type: pascal
    separator:
      char: '-'

# Vacuum
...
then:
  function: casing
  functionOptions: 
    type: pascal
    separator.char: '-'

Repro

Lib versions:

• @quobix/vacuum: 0.16.9
• @stoplight/spectral-cli: 6.15.0
• node: 22.14.0

I have a spectral rule that is defined as follows:

rules:
  must-use-pascal-case-on-headers:
    description: Headers must be Pascal-Case (w/ hyphens separators).
    message: "Header {{property}} must be Pascal-Case (capitalized and separated with hyphens)"
    severity: error
    given: 
      - $.paths.*.*.parameters[?(@ &&  @.in=='header')].name
      - $.paths.*.*.responses.*.headers[*]~
    then:
      function: casing
      functionOptions: 
        type: pascal
        separator:
          char: '-'

If I try running vacuum, then I get the following error:

'casing' function has invalid options supplied. Example valid options are 'type' = 'camel' or 'disallowDigits' = true: property 'separator' is not a valid property for 'casing'

If I fix my rule functionOptions this way:

rules:
  must-use-pascal-case-on-headers:
    description: Headers must be Pascal-Case (w/ hyphens separators).
    message: "Header {{property}} must be Pascal-Case (capitalized and separated with hyphens)"
    severity: error
    given: 
      - $.paths.*.*.parameters[?(@ &&  @.in=='header')].name
      - $.paths.*.*.responses.*.headers[*]~
    then:
      function: casing
      functionOptions: 
        type: pascal
        separator.char: '-'

Then it works in Vacuum, but fails in Spectral:

Error running Spectral!
Use --verbose flag to print the error stack.
Error #1: "casing" function does not support "separator.char" option

[daveshanley]

vacuum is mostly compatible with spectral. But they are different tools, built in different languages, using different architecture by different folks.