使用joi验证器时如何发送自定义响应json

Question

目前我的代码如下。 但我无法返回 json 对象。在理想情况下，我希望我的自定义响应如下所示。

var schema = Joi.object().keys({
  firstName: Joi.string().min(5).max(10).required().error(errors => {
    errors.forEach(err => {
      switch (err.type) {
        case "any.empty":
          err.message = "Value should not be empty!";
          break;
        case "string.min":
          err.message = `Value should have at least ${err.context.limit} characters!`;
          break;
        case "string.max":
          err.message = `Value should have at most ${err.context.limit} characters!`;
          break;
        default:
          break;
      }
    });
    return errors;
  }),
  // ...
}); 

错误响应。

{
status: 400,
code: '150003' -> this is a custom error code which is specific to my API.
message: 'The first name is missing.'
}