Support for .refine to use if in generated json schema

[akshay5995]

Hey, first of thanks for this amazing package 🙏🏽

I'd love to have support for .refine to generate corresponding if condition in the json schema

Example schema

const someSchema = z
  .object({
    enable: z.boolean().default(false),
    id: z.string().optional(),
  })
  .refine((data) => {
    if (data.enable && !data.id) {
      return false;
    }

    return true;
  }, "id should be specified");

generated

{
  "type": "object",
  "properties": {
    "enable": {
      "type": "boolean",
      "default": false
    },
    "id": {
      "type": "string"
    }
  },
  "additionalProperties": false,
  "$schema": "http://json-schema.org/draft-07/schema#"
}

expected

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "properties": {
    "enable": {
      "type": "boolean",
      "default": false
    },
    "id": {
      "type": "string"
    }
  },
  "if": {
    "properties": {
      "enable": {
        "const": true
      }
    }
  },
  "then": {
    "required": ["id"]
  },
  "else": {
    "properties": {
      "id": {
        "type": "string"
      }
    }
  }
}

Let me know if there's a workaround for it too. Thanks!

[StefanTerdell]

Thanks!

I don't think this is possible. The function defined in a refine could do anything, including side-effects. Your example is simple enough to be converted to a schema, yes - but that also means it could be expressed as a schema rather than in a refine. In this case, this would be the equivalent:

const someSchema = z.union([
  z
    .object({
      enable: z.literal(false).default(false),
      id: z.string(),
    })
    .partial(),
  z.object({
    enable: z.literal(true),
    id: z.string(),
  }),
]);

This would also give you type support, where as refine does not.

[akshay5995]

Thanks! Understood will close the issue.