README.md

pydantic to zod

This repo demonstrates a simple pathway for going from pydantic to zod via JSON schema. To use, run:

python recipe.py > schema.json
npm run generate

The input is recipe.py containing a simple pydantic model, and the ouptut is recipe.ts, TypeScript zod schema.

package.json

{
  "name": "pydantic-to-zod",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "generate": "json-refs resolve schema.json | json-schema-to-zod | prettier --parser typescript > schema.ts"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "json-refs": "^3.0.15",
    "json-schema-to-zod": "^2.0.14",
    "prettier": "^3.2.5",
    "zod": "^3.22.4"
  }
}

recipe.py

import json
from typing import List
from pydantic import BaseModel, Field

class Layer(BaseModel):
    name: str = Field(max_length=32, description="Layer name")

class Recipe(BaseModel):
    tileset: str = Field(max_length=32, description="Name of the tileset")
    minzoom: int = Field(ge=0, le=22, description="Minimum zoom")
    maxzoom: int = Field(ge=0, le=22, description="Maximum zoom")

    layers: List[Layer] = Field(description="Layers")

print(json.dumps(Recipe.model_json_schema(), indent=2))

schema.json

{
  "$defs": {
    "Layer": {
      "properties": {
        "name": {
          "description": "Layer name",
          "maxLength": 32,
          "title": "Name",
          "type": "string"
        }
      },
      "required": [
        "name"
      ],
      "title": "Layer",
      "type": "object"
    }
  },
  "properties": {
    "tileset": {
      "description": "Name of the tileset",
      "maxLength": 32,
      "title": "Tileset",
      "type": "string"
    },
    "minzoom": {
      "description": "Minimum zoom",
      "maximum": 22,
      "minimum": 0,
      "title": "Minzoom",
      "type": "integer"
    },
    "maxzoom": {
      "description": "Maximum zoom",
      "maximum": 22,
      "minimum": 0,
      "title": "Maxzoom",
      "type": "integer"
    },
    "layers": {
      "description": "Layers",
      "items": {
        "$ref": "#/$defs/Layer"
      },
      "title": "Layers",
      "type": "array"
    }
  },
  "required": [
    "tileset",
    "minzoom",
    "maxzoom",
    "layers"
  ],
  "title": "Recipe",
  "type": "object"
}

schema.ts

import { z } from "zod";

export default z.object({
  tileset: z.string().max(32).describe("Name of the tileset"),
  minzoom: z.number().int().gte(0).lte(22).describe("Minimum zoom"),
  maxzoom: z.number().int().gte(0).lte(22).describe("Maximum zoom"),
  layers: z
    .array(z.object({ name: z.string().max(32).describe("Layer name") }))
    .describe("Layers"),
});