pnpm add truth@npm:single-source-of-truth arktype

// src/shapes.ts

import { field, model, relation } from 'arktype';

export const User = model({
  id: field('string').id_(),
  name: field('string | null'),
  posts: () => relation(() => Post.array()),
});
export type User = typeof User.infer;
//           ^? { id: string, name: string | null }

export const Post = model({
  id: field('string').id_(),
  authorId: field('string'),
  title: field('string'),
  author: () => relation(() => User).reference('authorId', 'id'),
});
export type Post = typeof Post.infer;
//           ^? { id: string, authorId: string, title: string }

// truth.config.ts

import { defineConfig } from 'truth/config';

export default defineConfig(({ registry, arktype, prisma }) => {
  await arktype.import(registry, './src/shapes.ts');
  await prisma.export(registry, './prisma/generated.prisma');
});

truth

model User {
  id String @id
  name String?
  posts Post[]
}

model Post {
  id String @id
  authorId String
  title String
  author User @relation(fields: [authorId], references: [id])
}