Forked from https://github.com/anatine/zod-plugins to add support for components with $ref See: https://github.com/anatine/zod-plugins/pull/130

@woodle/zod-openapi

Converts a Zod schema to an OpenAPI SchemaObject as defined by openapi3-ts

Installation

Both openapi3-ts and zod are peer dependencies instead of dependant packages. While zod is necessary for operation, openapi3-ts is for type-casting.

yarn add openapi3-ts zod @woodle/zod-openapi

Usage

Take any Zod schema and convert it to an OpenAPI JSON object

import { generateSchema } from '@woodle/zod-openapi';
const aZodSchema = z.object({
  uid: z.string().nonempty(),
  firstName: z.string().min(2),
  lastName: z.string().optional(),
  email: z.string().email(),
  phoneNumber: z.string().min(10).optional(),
})
const myOpenApiSchema = generateSchema(aZodSchema);
// ...

This will generate an OpenAPI schema for myOpenApiSchema

{
  "type": "object",
  "properties": {
    "uid": {
      "type": "string",
      "minLength": 1
    },
    "firstName": {
      "type": "string",
      "minLength": 2
    },
    "lastName": {
      "type": "string"
    },
    "email": {
      "type": "string",
      "format": "email"
    },
    "phoneNumber": {
      "type": "string",
      "minLength": 10
    }
  },
  "required": [
    "uid",
    "firstName",
    "email"
  ]
}

Extend a Zod schema with additional OpenAPI schema via a function wrapper

import { extendApi, generateSchema } from '@woodle/zod-openapi';
const aZodExtendedSchema = extendApi(
      z.object({
        uid: extendApi(z.string().nonempty(), {
          title: 'Unique ID',
          description: 'A UUID generated by the server',
        }),
        firstName: z.string().min(2),
        lastName: z.string().optional(),
        email: z.string().email(),
        phoneNumber: extendApi(z.string().min(10), {
          description: 'US Phone numbers only',
          example: '555-555-5555',
        }),
      }),
      {
        title: 'User',
        description: 'A user schema',
      }
    );
const myOpenApiSchema = generateSchema(aZodExtendedSchema);
// ...

... or via extension of the Zod schema:

import { extendApi, generateSchema, extendZodWithOpenApi } from '@woodle/zod-openapi';
import {z} from 'zod';

extendZodWithOpenApi(z);

const aZodExtendedSchema = 
      z.object({
        uid: z.string().nonempty().openapi({
          title: 'Unique ID',
          description: 'A UUID generated by the server',
        }),
        firstName: z.string().min(2),
        lastName: z.string().optional(),
        email: z.string().email(),
        phoneNumber: z.string().min(10).openapi({
          description: 'US Phone numbers only',
          example: '555-555-5555',
        }),
      }).openapi(
      {
        title: 'User',
        description: 'A user schema',
      }
    );
const myOpenApiSchema = generateSchema(aZodExtendedSchema);
// ...

This will generate an extended schema:

{
  "type": "object",
  "properties": {
    "uid": {
      "type": "string",
      "minLength": 1,
      "title": "Unique ID",
      "description": "A UUID generated by the server"
    },
    "firstName": {
      "type": "string",
      "minLength": 2
    },
    "lastName": {
      "type": "string"
    },
    "email": {
      "type": "string",
      "format": "email"
    },
    "phoneNumber": {
      "type": "string",
      "minLength": 10,
      "description": "US Phone numbers only",
      "example": "555-555-5555"
    }
  },
  "required": [
    "uid",
    "firstName",
    "email",
    "phoneNumber"
  ],
  "title": "User",
  "description": "A user schema"
}

And why we are even here, using $ref,

// Make sure to use extendZodWithOpenApi() from @woodle/zod-nestjs
import { fragmentName } from '@woodle/zod-openapi';
const InternalSchema = extendApi(z.object({
    baz: z.string(),
}), {
    [fragmentName]: 'InternalSchemaDto'
})
export class InternalSchemaDto extends createZodDto(InternalSchema) { }

const MySchema = extendApi(z.object({
    foo: z.string()
    bar: InternalSchema,
})
class MySchemaDto extends createZodDto(MySchema) { }

@Controller()
@UsePipes(ZodValidationPipe)
@ApiExtraModels(InternalSchemaDto) // Must add referenct for Dto's that are not directly used.
export class AppController {
    constructor() { }

    @Post('hello')
    hello(@Body() body: MySchema) {
        return;
    }
}

Produces:

{
  "InternalSchemaDto": {
    "type": "object",
    "properties": {
      "baz": {
        "type": "string"
      }
    },
    "required": [
      "baz"
    ]
  },
  "MySchemaDto": {
    "type": "object",
    "properties": {
      "foo": {
        "type": "string"
      },
      "bar": {
        "$ref": "#/components/schemas/InternalSchemaDto"
      }
    },
    "required": [
      "foo",
      "bar"
    ]
  }
}

Credits

• anatine/zod-plugins

• express-zod-api

  A great lib that provided some insights on dealing with various zod types.

• zod-dto

  Lib providing insights into using Zod with NestJS