joi-to-json

joi-to-json

Objective

I have been using joi a lot in different Node.js projects to guard the API. It's The most powerful schema description language and data validator for JavaScript. as it said.

Many times, we need to utilize this schema description to produce other output, such as Swagger OpenAPI doc. That is why I build joi-route-to-swagger in the first place.

At the beginning, joi-route-to-swagger relies on joi-to-json-schema which utilizes many joi internal api or properties. I believed there was reason. Maybe joi did not provide the describe api way before. But I always feel uncomfortable and think it's time to move on.

The intention of joi-to-json is to support converting different version's joi schema to JSON Schema using describe api.

2.0.0 is out

It's a breaking change.

• Functionally, output format supports OpenAPI Schema other than purely JSON Schema.

• Technically, implementation theory has a big change:

  • In v1.0.0, it directly converts joi.describe() to JSON schema using different parser implementations.
  • In v2.0.0, joi.describe() of different versions are first converted to one base format, the latest version of joi.describe() output. Then different parsers (JSON, OpenAPI) all refer to this base format.

• The benefits of the change are:

  • Easier to retire old version of joi.
  • Easier to support more output formats.

Installation

npm install joi-to-json

Joi Version Support

• @commercial/joi
  • v12.1.0
• joi
  • 13.7.0
  • 14.3.1
• @hapi/joi
  • 15.1.1
  • 16.1.8
• joi
  • 17.4.2

For all above versions, I have tested one complex joi object fixtures which covers most of the JSON schema attributes that can be described in joi schema.

Although the versions chosen are the latest one for each major version, I believe it should be supporting other minor version as well.

Usage

Only one API parse is available. It's signature is parse(joiObj, type = 'json')

Currently supported output types:

• json - Default. Stands for JSON Schema Draft 07
• open-api - Stands for OpenAPI Schema
• json-draft-04 - Stands for JSON Schema Draft 04
• json-draft-2019-09 - Stands for JSON Schema Draft 2019-09

The output schema format are in outputs under specific folders for different types.

Sample code is as below:

const parse = require('joi-to-json')

const joiSchema = joi.object().keys({
  nickName: joi.string().required().min(3).max(20).example('鹄思乱想').description('Hero Nickname')
    .regex(/^[a-z]+$/, { name: 'alpha', invert: true }),
  avatar: joi.string().required().uri(),
  email: joi.string().email(),
  ip: joi.string().ip({ version: ['ipv4', 'ipv6'] }),
  hostname: joi.string().hostname().insensitive(),
  gender: joi.string().valid('Male', 'Female', '').default('Male'),
  height: joi.number().precision(2).positive().greater(0).less(200),
  birthday: joi.date().iso(),
  birthTime: joi.date().timestamp('unix'),
  skills: joi.array().items(joi.alternatives().try(
    joi.string(),
    joi.object().keys({
      name: joi.string().example('teleport').alphanum().lowercase().required().description('Skill Name'),
      level: joi.number().integer().min(10).max(100).default(50).multiple(10).example(10).description('Skill Level')
    })
  ).required()).min(1).max(3).unique().description('Skills'),
  tags: joi.array().items(joi.string().required()).length(2),
  retired: joi.boolean().truthy('yes').falsy('no').insensitive(false),
  certificate: joi.binary().encoding('base64'),
  notes: joi.any().meta({ 'x-supported-lang': ['zh-CN', 'en-US'], deprecated: true })
})

const jsonSchema = parse(joiSchema)
// Or parsing to OpenAPI schema through:
// const openApiSchema = parse(joiSchema, 'open-api')

Test

npm run test

You can optionally set below environment variables:

• CASE_PATTERN=joi-obj-17 to control which version of joi obj to test

Known Limitation

• For object.pattern usage in Joi, pattern parameter can only be a regular expression now as I cannot convert Joi object to regex yet.

Updates

Version 2.3.0

• Supports named link for schema resuse, such as .link('#person'). For open-api conversion, as the shared schemas are located in #/components/schemas which is not self-contained, the conversion result contains an extra schemas field so that you can extract it when required.

License

MIT