@polyprism/ts-domain-class

A Prisma 6 & 7 generator that emits opinionated TypeScript domain classes from your schema.prisma. Private fields, getters/setters with setter-driven data laundering, from() static factory, toJSON(), and a fluent builder. Part of PolyPrism.

const order = new Order({
  customerId: "cus_123",
  total: "10.99",         // stringified money from an HTTP API → coerced to Decimal
  placedAt: "2026-06-02", // ISO string → coerced to Date
});

await prisma.order.create({ data: order });  // pass directly — no destructure

Pure ESM, Prisma 7-native, one runtime dep (@polyprism/runtime). CI tests against both Prisma 6 and Prisma 7. The runtime dep is the price of admission for setter-driven data casting; the other PolyPrism patterns (ts-interface, ts-type, ts-class) stay zero-runtime-dep.

Install

pnpm add -D prisma @polyprism/ts-domain-class
pnpm add @polyprism/runtime

Note the split: the generator is a devDependency, the runtime is a real dependency.

Configure

generator polyprismCodegen {
  provider = "polyprism-ts-domain-class"
  output   = "../generated"
}

⚠️ The provider string is the bin name (no @scope/ prefix).

Run

pnpm prisma generate

What you get

• Setter-driven type laundering — Int / Float / Decimal / BigInt / DateTime fields coerce by default. Strings, booleans, enums, relations, and JSON columns stay strict.
• @noCoerce to opt a default-coerce field out (e.g. an internal counter you want strictly typed).
• @coerce(target) to opt a strict-by-default field in (e.g. String @coerce(int) for legacy stringified columns).
• @normalise(trim, lowercase, uppercase, nullEmptyToNull) to pipe string-typed fields through ordered transforms on assignment.
• Constructor: new User({ ... }) — object-arg with defaults applied for fields that have them.
• Prisma-friendly: prisma.user.create({ data: userInstance }) works directly because the instance exposes enumerable accessors. No toData() plumbing.
• JSON-safe: JSON.stringify(userInstance) produces wire-safe output natively. Models with BigInt columns also get a custom toJSON() so JSON.stringify doesn't throw on bigints.
• User.from(plainObject) static factory — hydrate a class instance from an untrusted shape (HTTP body, Prisma row, queue message). Assigns via setters so @coerce / @normalise fire on the way in; unknown keys are silently dropped.
• User.builder()...build() fluent builder with one chainable method per init-writable field.
• Everything ts-class gives you (standalone enum files, three-axis naming, JSDoc preservation, @db.X precision metadata, etc.).

Sibling patterns

• @polyprism/ts-interface — export interface User { ... }
• @polyprism/ts-type — export type User = { ... };
• @polyprism/ts-class — export class User { ... } with public fields (no setter pipeline)

License

MIT © Travis Fitzgerald