schema.js

var user = {

  name : [ purity.isString ], //Simple validation that the
                              //name is a string.

  email : [ purity.trim, purity.isString, purity.isEmail ],

  age : [ purity.isNumber, purity.greater(0), purity.toInt ],

  //Array of friends
  friends :  [{
            nickname: [purity.isString]
          }],

  comments : [], //Free-form field, anything can go in there.
}