exampleSchema.js

{
  // type as in the primitive type of the data
  type: Match.Any,
  // label on the form
  label: Match.Optional(Match.OneOf(String, Function)),
  // is it required to be submitted or not
  optional: Match.Optional(Match.OneOf(Boolean, Function)),
  // these four are self-explanatory.
  min: Match.Optional(Match.OneOf(Number, Date, Function)),
  max: Match.Optional(Match.OneOf(Number, Date, Function)),
  minCount: Match.Optional(Match.OneOf(Number, Function)),
  maxCount: Match.Optional(Match.OneOf(Number, Function)),
  // list of values that can be accepted
  allowedValues: Match.Optional(Match.OneOf([Match.Any], Function)),
  // if it's a number, does it have a decimal?
  decimal: Match.Optional(Boolean),
  exclusiveMax: Match.Optional(Boolean),
  exclusiveMin: Match.Optional(Boolean),
  // it must match this regex
  regEx: Match.Optional(Match.OneOf(RegExp, [RegExp])),
  // custom validation function
  custom: Match.Optional(Function),
  // whether or not to hide the keys of this object
  blackbox: Match.Optional(Boolean),
  // which value to make it by default
  autoValue: Match.Optional(Function),
  defaultValue: Match.Optional(Match.Any),
  // trim the strings or not
  trim: Match.Optional(Boolean),
  
  // my extension to the library. Defines formatters from library.
  fakeFormatter: Match.Optional(Function)
}

generateRandom.py

## Note: I have a package to generate random names
def generate_random(schema):
  """ generate a matching random entity for this schema key """
  if 'regex' in schema and 'fakeFormatter' not in schema:
    return RandExp.generate(schema.regex)
  elif 'fakeFormatter' in schema and 'regex' not in schema:
    return Faker.generate(schema.fakeFormatter)
  elif 'fakeFormatter' in schema and 'regex' in schema:
    ### this is where the problem comes in.
    temp = Faker.generate(schema.fakeFormatter)
    if not re.test(temp, schema.regex):
      generate_random(schema)
    else:
      return temp