This is a relic of the very first API. There is no reason to support both method(arg1, arg2, arg3) and method([arg1, arg2, arg3]). With new language features for working with arrays and expanding them as arguments, we should only support method(arg1, arg2, arg3). It is much more readable.

Require single array argument:

• Joi.alternatives()
• Joi.alternatives().try()

No longer supports array arguments:

• Joi.extend()
• Joi.any().allow()
• Joi.any().valid()
• Joi.any().invalid()
• Joi.array().items()
• Joi.array().ordered()
• Joi.boolean().truthy()
• Joi.boolean().falsy()
• Joi.object().xor()
• Joi.object().or()
• Joi.object().and()
• Joi.object().nand()
• Joi.object().requiredKeys()
• Joi.object().optionalKeys()
• Joi.object().forbiddenKeys()