A
arktype•2mo ago
Aidan Sunbury

toJsonSchema question

I am working on something that needs to convert standard schema validators to json schema. For seemingly similar validators, I am getting different behaviors between zod4's new json schema generatation and the arktype json schema generation that is leading to errors 
import { type } from "arktype";
import * as z4 from "zod/v4";

const testArktype = type({
  category: "string",
  priority: "'low' | 'medium' | 'high'",
  name: "string",
});

const testZod = z4.object({
  category: z4.string(),
  priority: z4.enum(["low", "medium", "high"]),
  name: z4.string(),
});

console.dir(z4.toJSONSchema(testZod), {
  depth: null,
});
// {
//   $schema: "https://json-schema.org/draft/2020-12/schema",
//   type: "object",
//   properties: {
//     category: {
//       type: "string",
//     },
//     priority: {
//       type: "string",
//       enum: [ "low", "medium", "high" ],
//     },
//     name: {
//       type: "string",
//     },
//   },
//   required: [ "category", "priority", "name" ],
//   additionalProperties: false,
// }


console.dir(testArktype.toJsonSchema(), {
  depth: null,
});
// {
//   $schema: "https://json-schema.org/draft/2020-12/schema",
//   type: "object",
//   properties: {
//     category: {
//       type: "string",
//     },
//     name: {
//       type: "string",
//     },
//     priority: {
//       enum: [ "high", "low", "medium" ],
//     },
//   },
//   required: [ "category", "name", "priority" ],
// }
import { type } from "arktype";
import * as z4 from "zod/v4";

const testArktype = type({
  category: "string",
  priority: "'low' | 'medium' | 'high'",
  name: "string",
});

const testZod = z4.object({
  category: z4.string(),
  priority: z4.enum(["low", "medium", "high"]),
  name: z4.string(),
});

console.dir(z4.toJSONSchema(testZod), {
  depth: null,
});
// {
//   $schema: "https://json-schema.org/draft/2020-12/schema",
//   type: "object",
//   properties: {
//     category: {
//       type: "string",
//     },
//     priority: {
//       type: "string",
//       enum: [ "low", "medium", "high" ],
//     },
//     name: {
//       type: "string",
//     },
//   },
//   required: [ "category", "priority", "name" ],
//   additionalProperties: false,
// }


console.dir(testArktype.toJsonSchema(), {
  depth: null,
});
// {
//   $schema: "https://json-schema.org/draft/2020-12/schema",
//   type: "object",
//   properties: {
//     category: {
//       type: "string",
//     },
//     name: {
//       type: "string",
//     },
//     priority: {
//       enum: [ "high", "low", "medium" ],
//     },
//   },
//   required: [ "category", "name", "priority" ],
// }
The arktype json schema output is missing the type annotation for priority, which is causing the library I am using to consume these json schemas to have issues. Is there any way to make the arktype json schema outputs fully verbose?
2 Replies
TizzySaurus
TizzySaurus•2mo ago
Tbf the ArkType output is valid JSON Schema. So if a library doesn't parse it I'd raise a bug report with the library I don't think there's anything you can do from ArkType's perspective Fwiw if you want the additionalProperties: false then you can "+": "reject" to disallow extra properties E.g.
const onlyFoo = type({"+": "reject", foo: "string"});
const onlyFoo = type({"+": "reject", foo: "string"});
Aidan Sunbury
Aidan SunburyOP•2mo ago
That's very fair. Unfortunately the other library is a lot less active / well maintained so I was kinda just hoping there was some king of config within arktype lol.

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