basic fluid validation in coffeescript

validator.coffee

class ValidationInstance
  constructor: (@item, @rules...) ->

class Validation 
  flatten = (arr) ->
    merged = [];
    merged.concat.apply(merged, arr);
  _toValidate = null
  instances = []
  
  RuleFor: (func) =>
    _toValidate = func(@)
    @
  
  NotEmpty: () =>
    func = (x="") -> x isnt "" and x.length > 0 and x isnt undefined
    instances.push(new ValidationInstance(_toValidate, func))
    @
    
  GreaterThan: (value) => 
    func = (x) -> x > value
    instances.push(new ValidationInstance(_toValidate, func))
    
  Validate: () =>
   flatten(instances.map((x) => x.rules.map((y)=> y(x.item))))
    
    
class UserValidator extends Validation
 constructor: (name, number) ->
  @RuleFor(() -> name)
   .NotEmpty()
    
  @RuleFor(() -> number)
   .GreaterThan(5)
  
class User extends UserValidator
  constructor: (name, number) ->
    super

u = new User("Name", 5);
console.log(u.Validate())