Customize generated code with printers

Set printer.nodes on TypeScript, Zod, or Faker plugins to change how schema types are emitted. Override only the handlers you need.

For callback signatures and context properties, see the AST reference.

TypeScript types

@kubb/plugin-ts builds TypeScript AST nodes, so a handler returns a ts.TypeNode created with the compiler's factory. This override prints date schemas as the JavaScript Date object instead of string.

date.ts

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

pluginTs({
  printer: {
    nodes: {
      date() {
        return ts.factory.createTypeReferenceNode('Date', [])
      },
    },
  },
})

Zod schemas

Write regular methods when you use this.base, this.transform, or this.options; arrow functions do not receive the printer context.

@kubb/plugin-zod prints expression strings, so a handler returns the Zod code as a string. With mini: true the same overrides target the Zod Mini printer instead.

date.ts

import { pluginZod } from '@kubb/plugin-zod'

pluginZod({
  printer: {
    nodes: {
      date() {
        return 'z.iso.date()'
      },
    },
  },
})

Use this.base to keep the default output and decorate it. This override appends .openapi(...) to every object schema, and nested nodes still print through the regular handlers.

openapi.ts

import { pluginZod } from '@kubb/plugin-zod'

pluginZod({
  printer: {
    nodes: {
      object(node) {
        return `${this.base(node)}.openapi(${JSON.stringify({ description: node.description })})`
      },
    },
  },
})

A Zod handler can also read this.options.direction, which is 'decode' while printing response schemas and 'encode' while printing request bodies and parameters. Return a different expression per direction and the plugin treats the node as a two-way conversion, emitting an ${name}InputSchema variant that request bodies resolve to. See Encode a custom type on requests.

Faker mocks

@kubb/plugin-faker also prints strings, one Faker expression per schema node. This override generates floats where the spec declares integers.

integer.ts

import { pluginFaker } from '@kubb/plugin-faker'

pluginFaker({
  printer: {
    nodes: {
      integer() {
        return 'faker.number.float()'
      },
    },
  },
})

Choose a customization

Use a printer for output-specific code such as Date or .openapi(...). Use a macro to change schema nodes before printing, or a resolver to change names and paths. Macros run before printer handlers.