如何在Node.js（Joi ^17.3.0版本）中验证嵌套对象并自定义错误提示信息

To get concise error messages like firstname required instead of the full path-based details.firstname is required, you have a few solid options with Joi v17.3.0:

Option 1: Per-Field Custom Messages #

The most straightforward approach is to explicitly define custom error messages for each required field. This gives you full control over each message:

const Joi = require("joi");
const Validation = (data) => {
  const schema = Joi.object({
    details: Joi.object({
      firstname: Joi.string()
        .required()
        .messages({
          'any.required': 'firstname required'
        }),
      lastname: Joi.string()
        .required()
        .messages({
          'any.required': 'lastname required'
        })
    })
  });
  return schema.validate(data);
};
module.exports = { Validation };

Option 2: Use Labels + Global Message Template #

If you have multiple fields and want to avoid repetition, set a custom label for each nested field and define a global message template for required fields:

const Joi = require("joi");
const Validation = (data) => {
  const schema = Joi.object({
    details: Joi.object({
      firstname: Joi.string().required().label('firstname'),
      lastname: Joi.string().required().label('lastname')
    })
  }).messages({
    'any.required': '{{#label}} required'
  });
  return schema.validate(data);
};
module.exports = { Validation };

Here, the label overrides the full path in error messages, and the global messages config ensures all required fields use the same concise format.

Option 3: Post-Process Error Messages #

For a scalable solution that works across all nested fields without modifying each one, you can post-process the validation error object to strip the parent path prefix:

const Joi = require("joi");
const Validation = (data) => {
  const schema = Joi.object({
    details: {
      firstname: Joi.string().required(),
      lastname: Joi.string().required(),
    },
  });
  const result = schema.validate(data);
  
  // Modify error messages if present
  if (result.error) {
    result.error.details = result.error.details.map(detail => {
      // Get the last part of the field path (e.g., 'firstname' from ['details', 'firstname'])
      const fieldName = detail.path.at(-1);
      detail.message = `${fieldName} required`;
      return detail;
    });
  }
  
  return result;
};
module.exports = { Validation };

This approach automatically adjusts all required field errors to use just the field name, regardless of how deeply nested they are.

Testing the Solution #

When you omit the firstname field in your request body, all three methods will return the error message firstname required instead of the original path-based message.

内容的提问来源于stack exchange，提问作者Arun M