Joi.date().iso() throws error when required() is used.

[fampinheiro]

The following code:

var Joi = require('joi');
Joi.validate('2014-12-02T11:00:20.000Z', Joi.date().iso().required());

throws:

/Users/fampinheiro/Workspace/projects/t-joi/node_modules/joi/node_modules/moment/moment.js:1060
            format = format.replace(localFormattingTokens, replaceLongDateForm
                            ^
TypeError: Object /^((\d{4}-[01]\d-[0-3]\dT[0-2]\d:[0-5]\d:[0-5]\d\.\d+([+-][0-2]\d:[0-5]\d|Z))|(\d{4}-[01]\d-[0-3]\dT[0-2]\d:[0-5]\d:[0-5]\d([+-][0-2]\d:[0-5]\d|Z))|(\d{4}-[01]\d-[0-3]\dT[0-2]\d:[0-5]\d([+-][0-2]\d:[0-5]\d|Z))|(\d{4}-[01]\d-[0-3]\d))$/ has no method 'replace'
    at expandFormat (/Users/fampinheiro/Workspace/projects/t-joi/node_modules/joi/node_modules/moment/moment.js:1060:29)
    at makeDateFromStringAndFormat (/Users/fampinheiro/Workspace/projects/t-joi/node_modules/joi/node_modules/moment/moment.js:1474:18)
    at makeMoment (/Users/fampinheiro/Workspace/projects/t-joi/node_modules/joi/node_modules/moment/moment.js:1798:17)
    at moment (/Users/fampinheiro/Workspace/projects/t-joi/node_modules/joi/node_modules/moment/moment.js:1832:16)
    at Object.internals.toDate (/Users/fampinheiro/Workspace/projects/t-joi/node_modules/joi/lib/date.js:63:24)
    at internals.Date._base (/Users/fampinheiro/Workspace/projects/t-joi/node_modules/joi/lib/date.js:28:46)
    at internals.Any._validate (/Users/fampinheiro/Workspace/projects/t-joi/node_modules/joi/lib/any.js:371:31)
    at internals.Any._validateWithOptions (/Users/fampinheiro/Workspace/projects/t-joi/node_modules/joi/lib/any.js:425:23)
    at root.validate (/Users/fampinheiro/Workspace/projects/t-joi/node_modules/joi/lib/index.js:102:23)
    at Object.<anonymous> (/Users/fampinheiro/Workspace/projects/t-joi/index.js:2:5)