Angular directive to validate input based on maximum words length.

ngmaxwords.coffee

'use strict'

###*
 # @ngdoc directive
 # @name app.directive:ngMaxwords
 # @description Angular directive to validate input based on maximum words length.
 # # ngMaxwords
###
angular.module 'app'
  .directive 'ngMaxwords', ->
    restrict: 'A'
    require: '?ngModel'
    link: (scope, element, attrs, ctrl) ->

      if (!ctrl)
        return

      maxwords = 0

      attrs.$observe('ngMaxwords', (value) ->
        intval = parseInt(value)
        maxwords = angular.isNumber(intval) ? intval : -1
        ctrl.$validate()
      )

      ctrl.$validators.maxwords = (modelValue, viewValue) ->
        (maxwords < 0) || ctrl.$isEmpty(viewValue) || (viewValue.match(/\S+/g).length <= maxwords)