Migration: @kubb/plugin-ts

Part of the v4 → v5 migration guide. See the full option reference in @kubb/plugin-ts.

Removed: mapper

v4 kubb.config.ts

pluginTs({ mapper: { status: 'string' } })

Use printer.nodes to override a schema-type renderer, or macros to rewrite AST nodes before printing.

Removed: paramsCasing

v4 kubb.config.ts

pluginTs({ paramsCasing: 'camelcase' })

Parameter properties inside the generated PathParams, QueryParams, HeaderParams, and RequestConfig types are now always camelCase. In v4 they defaulted to the original spec names, and paramsCasing: 'camelcase' opted into the new behavior. v5 makes camelCase the only option, so drop the setting.

Generated output

// OpenAPI spec uses: pet_id, X-Api-Key
export type GetPetPathParams = { petId: string } // was { pet_id: string }
export type GetPetHeaderParams = { xApiKey?: string } // was { 'X-Api-Key'?: string }

Changed: RequestConfig groups request input

The generated *RequestConfig type now groups every request input under { path, query, body, headers } so the client, query, and Cypress plugins all share one call shape. Each key holds the matching *PathParams, *QueryParams, *Data, or *HeaderParams type, or never when the operation has none. The path, query, and headers keys are required when the operation has a required parameter in that group, and the unused keys are typed never so passing them is a compile error.

Generated output

export type GetPetRequestConfig = {
  path: { petId: string } // required: the operation has a required path param
  query?: GetPetQueryParams
  body?: never
  headers?: never
  url: '/pet/{petId}'
}

export type AddPetRequestConfig = {
  path?: never
  query?: never
  body: AddPetData
  headers?: never
  url: '/pet'
}

The grouped object is what every generated client function, hook, and Cypress helper takes as its first argument, typed Omit<XxxRequestConfig, 'url'>. See the client plugin removal note, plugin-react-query, and plugin-cypress pages for the call-site changes.

Renamed: transformers.name

resolver.resolveTypeName replaces transformers.name.

Moved to adapterOas

dateType, integerType, unknownType, emptySchemaType, enumSuffix, and contentType moved to adapterOas. See Migration: @kubb/adapter-oas.

Changed: enum options grouped under one object

The loose enumType, enumTypeSuffix, and enumKeyCasing options now live inside one enum object. A new enum.constCasing sets the casing of the generated const. The old enumType: 'asPascalConst' is gone. Use constCasing: 'pascalCase' instead.

v4 (old)	v5 (new)
enumType: 'asConst'	enum: { type: 'asConst' }
enumType: 'asPascalConst'	enum: { type: 'asConst', constCasing: 'pascalCase' }
enumTypeSuffix: 'Value'	enum: { typeSuffix: 'Value' }
enumKeyCasing: 'screamingSnakeCase'	enum: { keyCasing: 'screamingSnakeCase' }

v4 kubb.config.ts

import { defineConfig } from '@kubb/core'
import { pluginTs } from '@kubb/plugin-ts'

export default defineConfig({
  input: { path: './petstore.yaml' },
  output: { path: './src/gen' },
  plugins: [
    pluginTs({
      enumType: 'asConst',
      enumTypeSuffix: 'Key',
      enumKeyCasing: 'none',
    }),
  ],
})

v5 kubb.config.ts

import { defineConfig } from 'kubb'
import { pluginTs } from '@kubb/plugin-ts'

export default defineConfig({
  input: { path: './petstore.yaml' },
  output: { path: './src/gen' },
  plugins: [
    pluginTs({
      enum: { type: 'asConst', constCasing: 'camelCase', typeSuffix: 'Key', keyCasing: 'none' },
    }),
  ],
})

TIP

Set constCasing: 'pascalCase' with typeSuffix: '' to emit a const and a type that share the schema's exact name. Most hand-written codebases use this convention, so existing annotations and value references keep working.

v5 kubb.config.ts

pluginTs({ enum: { type: 'asConst', constCasing: 'pascalCase', typeSuffix: '' } })

Generated output

export const VehicleType = {
  Sedan: 'Sedan',
  SUV: 'SUV',
} as const

export type VehicleType = (typeof VehicleType)[keyof typeof VehicleType]

Generated output

Enums: object literal instead of enum

v5 emits a const-asserted object plus a *Key type union. This drops the runtime cost of a TypeScript enum and stays tree-shakeable.

Generated output

export enum ParamsStatusEnum {
export enum orderParamsStatusEnum { 
  placed = 'placed',
  approved = 'approved',
  delivered = 'delivered',
}

status: ParamsStatusEnum
status: OrderParamsStatusEnumKey

Enum names are now operation-scoped (orderParamsStatusEnum, customerParamsStatusEnum) instead of suffix-deduplicated (ParamsStatusEnum, ParamsStatusEnum2), so the numeric collisions are gone. Configure enum on pluginTs when you want enum, constEnum, literal, or a different const and type casing.

int64 maps to bigint by default

adapterOas defaults integerType to 'bigint', so OpenAPI fields with format: int64 generate bigint instead of number.

Diff

- petId?: number
+ petId?: bigint

Set integerType: 'number' on adapterOas to restore the previous output.

Open string unions use (string & {})

v5 writes the known TypeScript trick to keep IntelliSense suggestions.

Diff

- status?: 'accepted' | string
+ status?: 'accepted' | (string & {})

JSDoc

The format suffix drops off the @type tag (@type integer | undefined, int64 becomes @type integer | undefined), since the schema already documents the format. v5 emits @example from the OpenAPI example field, and object schemas now carry an @type object tag.

Discriminated unions are factored

Fields shared by every variant of a oneOf/anyOf move into a common object:

Diff

- export type Pet =
-   | { id?: number; name: string; status?: StatusEnum; ... }
-   | { id?: number; name: string; status?: StatusEnum; ... }
+ export type Pet = ({ ... } | { ... }) & {
+   id?: number
+   name: string
+   status?: PetStatusEnumKey
+   ...
+ }