Support schema keys with '.' (without forcing path reach)

[peterkuiper]

Context

• node version: v8.11.4
• joi version: v14.0.0+
• environment (node, browser): node
• used with (hapi, standalone, ...): standalone
• any other relevant information: Schema below works with v13. We upgraded Joi and some of our tests failed.

What are you trying to achieve or the steps to reproduce ?

const schema = Joi.object().keys({
  'mail.from': Joi.string().lowercase().email().optional(),
  'mail.url': Joi.string().uri({ scheme: ['https'] }).optional(),
}).xor(
  'mail.from',
  'mail.url',
);

Joi.validate({ 'mail.url': 'https://example.com' }, schema));

Removing .xor() seems to fix the validation.

Which result you had ?

{ error:
   { ValidationError: "value" must contain at least one of [mail.from, mail.url]
    at Object.exports.process (node_modules/joi/lib/errors.js:201:19)
    at internals.Object._validateWithOptions (node_modules/joi/lib/types/any/index.js:722:31)
    at module.exports.internals.Any.root.validate node_modules/joi/lib/index.js:146:23)
    at Object.<anonymous> (joi.js:13:17)
    at Module._compile (module.js:652:30)
    at Object.Module._extensions..js (module.js:663:10)
    at Module.load (module.js:565:32)
    at tryModuleLoad (module.js:505:12)
    at Function.Module._load (module.js:497:3)
    at Function.Module.runMain (module.js:693:10)
     isJoi: true,
     name: 'ValidationError',
     details: [ [Object] ],
     _object: { 'mail.url': 'https://example.com' },
     annotate: [Function] },
  value: { 'mail.url': 'https://example.com' },
  then: [Function: then],
  catch: [Function: catch] }

What did you expect ?

{ error: null,
  value: { 'mail.url': 'https://example.com' },
  then: [Function: then],
  catch: [Function: catch] }

[hueniverse]

The problem is that many methods support key reaching (e.g. a.b is translated into ['a']['b']).