Custom validator for unknown formats

First of all, great module! It is working really well and saved us a lot of time.

There is an option unknownFormats to ignore custom formats. Is it possible to write your own validator and somehow inject it? Would be nice if I could use the base of this module instead of writing extra code to do same as this module does. Any other suggestions are welcome as well.

[cdimascio]

this feature is available in v4.4.0

e.g.

formats: [
  {
    name: 'my-three-digit-format',
    type: 'number',
    // validate returns true the number has 3 digits, false otherwise
    validate: v => /^\d{3}$/.test(v.toString()) 
  },
  {
    name: 'my-three-letter-format',
    type: 'string',
    // validate returns true the string has 3 letters, false otherwise
    validate: v => /^[A-Za-z]{3}$/.test(v)
  },
]

[rscarson]

A lot of custom formats could be validated automatically; if the pattern field was set, you could check against the enclosed regex to validate.