CODE EXAMPLE FOR JAVASCRIPT

joi validation custom message in node

const Joi = require('Joi');

const schema = Joi.object({
    username: Joi.string()
      .min(2)
      .max(30)
      .required()
      .pattern(new RegExp(/^(?!.*..)(?!.*.$)[^W][w.]{0,29}$/))
      .message({"string.pattern.base":"Invalid username",
                "string.min":"minimum 2 character required",
                "string.max":"maximum 30 characters allowed"})
});
//
messages: {
      'any.custom': [Object],
      'any.default': [Object],
      'any.failover': [Object],
      'any.invalid': [Object],
      'any.only': [Object],
      'any.ref': [Object],
      'any.required': [Object],
      'any.unknown': [Object],
      'string.alphanum': [Object],
      'string.base': [Object],
      'string.base64': [Object],
      'string.creditCard': [Object],
      'string.dataUri': [Object],
      'string.domain': [Object],
      'string.email': [Object],
      'string.empty': [Object],
      'string.guid': [Object],
      'string.hex': [Object],
      'string.hexAlign': [Object],
      'string.hostname': [Object],
      'string.ip': [Object],
      'string.ipVersion': [Object],
      'string.isoDate': [Object],
      'string.isoDuration': [Object],
      'string.length': [Object],
      'string.lowercase': [Object],
      'string.max': [Object],
      'string.min': [Object],
      'string.normalize': [Object],
      'string.token': [Object],
      'string.pattern.base': [Object],
      'string.pattern.name': [Object],
      'string.pattern.invert.base': [Object],
      'string.pattern.invert.name': [Object],
      'string.trim': [Object],
      'string.uri': [Object],
      'string.uriCustomScheme': [Object],
      'string.uriRelativeOnly': [Object],
      'string.uppercase': [Object]
}
//$uj@y