Json-Schema-to-Zodex

Summary

A runtime package and CLI tool to convert JSON schema (draft 4+) objects or files into Zodex schemas.

This is a fork of json-schema-to-zod which seeks to allow dynamic evaluation without the need for eval.

Note that with the ability to convert to Zodex JSON, some of the export options are no longer relevant and may be removed.

Looking for the opposite? Check out zod-to-json-schema

Usage

CLI

Simplest example

npm i -g json-schema-to-zodex

json-schema-to-zodex -i mySchema.json -o mySchema.ts

Example with $refs resolved and output formatted

npm i -g json-schema-to-zodex json-refs prettier

json-refs resolve mySchema.json | json-schema-to-zodex | prettier --parser typescript > mySchema.ts

Options

| Flag | Shorthand | Function | | -------------- | --------- | ---------------------------------------------------------------------------------------------- | | --input | -i | JSON or a source file path. Required if no data is piped. | | --output | -o | A file path to write to. If not supplied stdout will be used. | | --name | -n | The name of the schema in the output | | --depth | -d | Maximum depth of recursion in schema before falling back to z.any(). Defaults to 0. | | --module | -m | Module syntax; esm, cjs or none. Defaults to esm in the CLI and none programmaticly. | | --type | -t | Export a named type along with the schema. Requires name to be set and module to be esm. | | --withJsdocs | -wj | Generate jsdocs off of the description property. |

Programmatic

Simple example

import { jsonSchemaToZodex } from "json-schema-to-zodex";

const myObject = {
  type: "object",
  properties: {
    hello: {
      type: "string",
    },
  },
};

// `type` can be either a string or - outside of the CLI - a boolean. If its `true`, the name of the type will be the name of the schema with a capitalized first letter.

const justTheSchema = jsonSchemaToZodex(myObject);

Example with $refs resolved and output formatted

import { z } from "zod";
import { resolveRefs } from "json-refs";
import { format } from "prettier";
import jsonSchemaToZodex from "json-schema-to-zodex";

async function example(jsonSchema: Record<string, unknown>): Promise<string> {
  const { resolved } = await resolveRefs(jsonSchema);
  const code = jsonSchemaToZodex(resolved);
  const formatted = await format(code, { parser: "typescript" });

  return formatted;
}

Overriding a parser

You can pass a function to the parserOverride option, which represents a function that receives the current schema node and the reference object, and should return a string when it wants to replace a default output. If the default output should be used for the node just return void.

Schema factoring

Factored schemas (like object schemas with "oneOf" etc.) is only partially supported. Here be dragons.

Use at Runtime

JSON Schema and Zod does not overlap 100% and the scope of the parsers are purposefully limited in order to help the author avoid a permanent state of chaotic insanity. As this may cause some details of the original schema to be lost in translation, it is instead recommended to use tools such as Ajv to validate your runtime values directly against the original JSON Schema.