additionalTypes Plugin

A custom Hey API plugin that generates TypeScript union types for all tags and operation IDs found in your OpenAPI schema.

Its main purpose is to provide strongly-typed constants for use with React Query meta invalidation — so instead of plain strings you get compile-time safety when referencing tags or operation IDs.

Generated output

Given an OpenAPI schema with operations tagged users, products, and operation IDs getUsers, createUser, the plugin generates:

// additionalTypes.gen.ts
export type AvailableTags = 'products' | 'users';
export type AvailableOperationIds = 'createUser' | 'getUsers';

Both unions are sorted alphabetically. If no tags / operation IDs exist in the schema, the type falls back to never.

Installation

Copy additionalTypes.ts into your project alongside your openapi-ts.config.ts.

your-project/
├── openapi-ts.config.ts
├── additionalTypes.ts   ← plugin file
└── src/
    └── client/          ← generated output

Usage

// openapi-ts.config.ts
import { defineConfig } from '@hey-api/openapi-ts';
import { additionalTypesConfig } from './additionalTypes.js';

export default defineConfig({
  input: './openapi.yaml',
  output: 'src/client',
  plugins: [
    '@hey-api/typescript',
    additionalTypesConfig(),
  ],
});

With options

additionalTypesConfig({
  generateTags: true,
  generateOperationIds: false,
  tagsTypeName: 'ApiTag',
})

Options

Option	Type	Default	Description
generateTags	boolean	true	Generate union type of all operation tags
generateOperationIds	boolean	true	Generate union type of all operation IDs
tagsTypeName	string	'AvailableTags'	Name of the generated tags union type
operationIdsTypeName	string	'AvailableOperationIds'	Name of the generated operation IDs union type