javascript - 如何在Joi中添加自定义验证器功能？

Question

我有 Joi 架构，并且想要添加一个自定义验证器来验证默认 Joi 验证器无法实现的数据。

目前我使用的是Joi 16.1.7版本

const method = (value, helpers) => {
  // for example if the username value is (something) then it will throw an 
  // error with the following message but it throws an error inside (value) 
  // object without error message. It should throw error inside the (error) 
  // object with a proper error message
        
  if (value === "something") {
    return new Error("something is not allowed as username");
  }

  return value; // Return the value unchanged
};
        
const createProfileSchema = Joi.object().keys({
  username: Joi.string()
    .required()
    .trim()
    .empty()
    .min(5)
    .max(20)
    .lowercase()
    .custom(method, "custom validation")
});
        
const { error, value } = createProfileSchema.validate({
  username: "something" 
});
        
console.log(value); // returns {username: Error}
console.log(error); // returns undefined

但我无法以正确的方式实现它。我读过 Joi 文档，但对我来说似乎有点令人困惑。谁能帮我解答一下吗？

Answer 1

const Joi = require('@hapi/joi');
    
Joi.object({
  password: Joi
    .string()
    .custom((value, helper) => {
      if (value.length < 8) {
        return helper.message("Password must be at least 8 characters long");
      }

      return true;
    })
}).validate({
    password: '1234'
});