Simple coffee validation

validation.coffee

kindof = (x) ->
  if x? then x.constructor else x


validateWithFunction = (object, func) ->
  true_or_reason = func(object)
  if true_or_reason is true
    { valid: true }
  else
    { valid: false, reason: true_or_reason }


validateWithObject = (object, schema) ->
  result = {}
  result[key] = validate(object[key], schema[key]) for key of schema
  result


validate = (object, desc, debug = true) ->
  result = switch kindof(desc)
    when Object   then validateWithObject(object, desc)
    when Function then validateWithFunction(object, desc)

  if debug # these are non-enumerable
    Object.defineProperty(result, '$object', value: object)
    Object.defineProperty(result, '$desc', value: desc)

  return result


is_2 = (x) ->
  x is 2 or "x is not 2"

is_person = (person) ->
  validate person,
    name: (name) ->
      switch
        when kindof(name) isnt String then "Not a string"
        when name.length is 0 then "Name is empty"
        else true

    age: (age) ->
      switch
        when kindof(age) isnt Number then "Not a number"
        when age < 1 then "Must be >= 1"
        else true


test = (object, desc) ->
  log object
  # log desc.name
  log validate(object, desc)
  log '-'


# test 1, is_2
test {}, is_person
test { age: 3 }, is_person