String allow null conversion about joi-to-swagger

[Twipped]

You're right, it's not valid swagger by the spec. This was an extension to swagger that we used at Shutterstock because otherwise there was no way to define a property that could be null. The libraries we used back then supported it (curiously, I thought Swagger UI was one of them).

There is also no null type. Swagger 3.0 added the nullable: true attribute. I don't have the time right now to change this lib to use it, but I'd welcome a pull request that switched to that behavior.

[martinmacko47]

You mean a PR to add nullable: true instead of type: ["string", "null"], or to remove null from type: ["string", "null"].

To which swagger verion joi-to-swagger targets? To 2.0 or to 3.0? So we won't start generating invalid schema again as swagger 2.0 does not support nullable: true.

[Twipped]

The former.

IMO Swagger 2 is a fundamentally flawed spec, I see no reason to continue to support it now that 3 is out. This change would probably merit a major version bump, however.

[Twipped]

Fixed in 2.0 release

[deskoh]

See ajv-validator/ajv#1471. Enum doesn't play well with nullable.

This schema

const schema = joi
  .object({
    field1: joi.valid("a", "b", null)
  })
  .unknown();

below generates:

{
  "type": "object",
  "properties": {
    "field1": {
      "enum": ["a", "b"],
      "nullable": true
    }
  }
} 

The correct schema should be

{
  "type": "object",
  "properties": {
    "field1": {
      "enum": ["a", "b", null]
      "nullable": true
    }
  }
} 

nullable flag and null are required

Codesandbox link https://codesandbox.io/s/json-schema-enum-nullable-zsrlbj?file=/src/index.test.js