Generators

Generators transform your opensaas.config.ts into Prisma schemas and TypeScript types.

Overview

The generator system reads your declarative config and creates:

Prisma Schema (prisma/schema.prisma)
TypeScript Types (.opensaas/types.ts)
Context Factory (.opensaas/context.ts)

Running the Generator

bash

pnpm opensaas generate

Or in a specific example:

bash

cd examples/blog
pnpm generate

What Gets Generated

1. Prisma Schema

From your config:

typescript

Post: list({
  fields: {
    title: text({ validation: { isRequired: true } }),
    author: relationship({ ref: 'User.posts' }),
  },
})

The generator creates:

prisma

model Post {
  id        String   @id @default(cuid())
  title     String
  authorId  String
  author    User     @relation(fields: [authorId], references: [id])
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt
}

2. TypeScript Types

Type-safe types for all your lists:

typescript

export type Lists = {
  Post: {
    fields: {
      title: string
      author: User
    }
  }
  // ... more lists
}

3. Context Factory

Auto-generated context creation function:

typescript

import { getContext } from '@/.opensaas/context'

const context = await getContext({ userId: '123' })

Generator Architecture

Generators delegate to field builder methods rather than using switch statements. Each field type provides its own generation logic:

typescript

text({
  getPrismaType: (fieldName) => {
    return { type: 'String', modifiers: '?' }
  },
  getTypeScriptType: () => {
    return { type: 'string', optional: true }
  },
})

This allows field types to be fully self-contained and extensible.

Custom Prisma Client Constructor

To use custom database drivers (e.g., Neon, Turso, PlanetScale), provide a prismaClientConstructor:

typescript

export default config({
  db: {
    provider: 'postgresql',
    url: process.env.DATABASE_URL,
    prismaClientConstructor: (PrismaClient) => {
      const adapter = new PrismaNeon({
        connectionString: process.env.DATABASE_URL,
      })
      return new PrismaClient({ adapter })
    },
  },
  // ... rest of config
})

Generator Limitations

Current generators are basic:

❌ No migration support (use prisma db push)
❌ No introspection support
❌ Limited Prisma features (no raw queries, advanced transactions)

Best Practices

1. Regenerate After Config Changes

Always run the generator after modifying your config:

bash

pnpm generate

2. Commit Generated Files

Commit the generated files to version control for consistency:

bash

git add prisma/schema.prisma
git add .opensaas/
git commit -m "Regenerate schema"

3. Use Type-Safe Operations

Use the generated types for type safety:

typescript

import type { Lists } from '@/.opensaas/types'

const post: Lists['Post'] = await context.db.post.findUnique({
  where: { id: '123' },
})

Next Steps

Config System - Learn about config options
Field Types - Available field types