   @return {boolean} The validation result.
 ###
 spark.validation.isEmail = (value) ->
-  if goog.isString value
+  if spark.validation.isString value
     return spark.validation.EMAIL_REGEX.test value
 
   return no

  @return {boolean} The validation result.
###
spark.validation.isText = (value) ->
  if goog.isString value
    return value.length > 0

  return no

  @return {boolean} The validation result.
###
spark.validation.hasMinLength = (value, minLength) ->
  if spark.validation.isString value
    return value.length >= minLength

  return no
