feat: DateTime maps to DateFromInput dual-boundary schema (#24)

Generated DateTime columns previously used Schema.DateFromSelf
(Encoded = Date) which broke RPC/HTTP wire decode where JSON-parsed
input is a string. Adds a new exported DateFromInput schema —
Schema.Union(Schema.DateFromSelf, Schema.Date) — wired into the
codegen, so decode accepts native Date instances (Kysely DA layer)
AND ISO strings (RPC wire layer). Encode picks the first union member
(DateFromSelf, identity) so Kysely-bound encode keeps producing Date
instances.

Mirrors the JsonValue dual-boundary discipline already in this package
(Schema<JsonValue, JsonValue> is wire-safe by construction).

Internal: consolidated duplicated PRISMA_TO_EFFECT_SCHEMA /
PRISMA_SCALAR_MAP constants. src/effect/type.ts now imports the
canonical map from src/utils/type-mappings.ts.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: samuelho-dev

.changeset/datetime-dual-input.md

@@ -0,0 +1,41 @@
+---
+"prisma-effect-kysely": minor
+---
+
+feat: DateTime columns now map to `DateFromInput` (dual-boundary Date schema)
+
+`DateTime` columns previously mapped to `Schema.DateFromSelf`
+(`Encoded = Date`), which broke RPC/HTTP wire decode where JSON-parsed
+input is a string. Now maps to a new exported `DateFromInput` schema:
+
+- **Type** = `Date` (runtime — unchanged)
+- **Encoded** = `Date | string` (was `Date`)
+
+Defined as `Schema.Union(Schema.DateFromSelf, Schema.Date)`, so decode
+accepts native `Date` instances (Kysely DA layer — pg driver returns Date)
+AND ISO strings (RPC/HTTP wire layer — JSON.parse output). One primitive
+serves both consumer boundaries; consumers no longer need parallel
+schemas or `Schema.extend` overrides for date columns.
+
+**Why minor (not major)**: existing public API behavior is preserved.
+`Selectable<T>` / `Insertable<T>` / `Updateable<T>` Type sides unchanged.
+Decode accepts MORE inputs (Date AND string), not fewer. Encode picks
+the first union member (`DateFromSelf`, identity) so Kysely-bound
+encode still produces Date instances — existing call sites keep working.
+
+**Why the change**: `DateFromSelf` optimized for the in-memory Kysely
+boundary; `Schema.Date` optimizes for the JSON wire boundary. Modern
+apps cross both with the same generated schemas. Picking either single
+primitive forced consumers to patch around it at one boundary.
+`DateFromInput` accepts both encoded shapes natively. Mirrors the
+`JsonValue` dual-boundary discipline already in this package
+(`Schema<JsonValue, JsonValue>` is wire-safe by construction).
+
+**Migration**: no code changes for typical consumers. If you imported
+`Schema.DateFromSelf` directly from generated `types.ts` in a way that
+depended on the literal symbol, switch to `DateFromInput` imported from
+`prisma-effect-kysely`.
+
+**Internal**: consolidated duplicated `PRISMA_TO_EFFECT_SCHEMA` /
+`PRISMA_SCALAR_MAP` constants. `src/effect/type.ts` now imports the
+canonical map from `src/utils/type-mappings.ts`.

CLAUDE.md

@@ -62,7 +62,7 @@ export type UserId = typeof UserId.Type;
 export const User = Schema.Struct({
   id: columnType(Schema.UUID, Schema.Never, Schema.Never),
   email: Schema.String,
-  createdAt: generated(Schema.DateFromSelf),
+  createdAt: generated(DateFromInput),
 });
 export type User = typeof User;
 
@@ -97,17 +97,19 @@ Prisma stores `A`/`B` columns; we emit semantic snake_case fields via `Schema.pr
 
 ## Type mappings
 
-| Prisma      | Effect                | Notes              |
-| ----------- | --------------------- | ------------------ |
-| String      | `Schema.String`       | UUID → `Schema.UUID` |
-| Int / Float | `Schema.Number`       |                    |
-| BigInt      | `Schema.BigInt`       |                    |
-| Decimal     | `Schema.String`       | precision          |
-| Boolean     | `Schema.Boolean`      |                    |
-| DateTime    | `Schema.DateFromSelf` |                    |
-| Json        | `Schema.Unknown`      |                    |
-| Bytes       | `Schema.Uint8Array`   |                    |
-| Enum        | imported enum schema  |                    |
+| Prisma      | Effect                | Notes                                  |
+| ----------- | --------------------- | -------------------------------------- |
+| String      | `Schema.String`       | UUID → `Schema.UUID`                   |
+| Int / Float | `Schema.Number`       |                                        |
+| BigInt      | `Schema.BigInt`       |                                        |
+| Decimal     | `Schema.String`       | precision                              |
+| Boolean     | `Schema.Boolean`      |                                        |
+| DateTime    | `DateFromInput`       | dual-input: `Date \| string` ↔ `Date`  |
+| Json        | `JsonValue`           | recursive JSON, wire-safe              |
+| Bytes       | `Schema.Uint8Array`   |                                        |
+| Enum        | imported enum schema  |                                        |
+
+`DateFromInput` is `Schema.Union(Schema.DateFromSelf, Schema.Date)` — accepts native `Date` (Kysely DA boundary) and ISO strings (RPC/HTTP wire boundary). Encode picks the first union member (DateFromSelf identity) so Kysely-bound paths still receive Date instances.
 
 Arrays → `Schema.Array(t)`. Nullable → `Schema.NullOr(t)`.
 
@@ -130,7 +132,7 @@ Arrays → `Schema.Array(t)`. Nullable → `Schema.NullOr(t)`.
 
 ## Working in this repo
 
-- Run `bun run test` (280 tests) to baseline before changes
+- Run `bun run test` to baseline before changes
 - Generator must be rebuilt before `prisma generate` picks up changes
 - Test fixtures: `src/__tests__/fixtures/test.prisma`
 - Generated headers include timestamp + edit warning

README.md

@@ -27,7 +27,7 @@ Three files: `enums.ts`, `types.ts`, `index.ts`.
 
 ```typescript
 import { Schema } from "effect";
-import { columnType, generated, Selectable } from "prisma-effect-kysely";
+import { columnType, DateFromInput, generated, Selectable } from "prisma-effect-kysely";
 
 // Branded ID
 export const UserId = Schema.UUID.pipe(Schema.brand("UserId"));
@@ -37,7 +37,7 @@ export type UserId = typeof UserId.Type;
 export const User = Schema.Struct({
   id: columnType(Schema.UUID, Schema.Never, Schema.Never),
   email: Schema.String,
-  createdAt: generated(Schema.DateFromSelf),
+  createdAt: generated(DateFromInput),
 });
 export type User = typeof User;
 
@@ -80,13 +80,13 @@ Schema names are PascalCase regardless of Prisma model name (`session_preference
 | BigInt      | `Schema.BigInt`       |
 | Decimal     | `Schema.String`       |
 | Boolean     | `Schema.Boolean`      |
-| DateTime    | `Schema.DateFromSelf` |
-| Json        | `Schema.Unknown`      |
+| DateTime    | `DateFromInput`       |
+| Json        | `JsonValue`           |
 | Bytes       | `Schema.Uint8Array`   |
 | Enum        | `Schema.Literal(...)` |
 | UUID        | `Schema.UUID`         |
 
-Arrays → `Schema.Array(t)`. Nullable → `Schema.NullOr(t)`.
+Arrays → `Schema.Array(t)`. Nullable → `Schema.NullOr(t)`. `DateFromInput` accepts `Date | string` on the encoded side; `JsonValue` is `Schema<JsonValue, JsonValue>`. Both are wire-safe (`JSON.parse` output decodes cleanly).
 
 ## UUID Detection
 

src/__tests__/brand-preservation.test.ts

@@ -10,7 +10,14 @@
 
 import { Schema } from 'effect';
 import { describe, it, expectTypeOf } from 'vitest';
-import { columnType, generated, Insertable, VariantTypeId, VariantMarker } from '../kysely/helpers';
+import {
+  columnType,
+  DateFromInput,
+  generated,
+  Insertable,
+  VariantTypeId,
+  VariantMarker,
+} from '../kysely/helpers';
 
 describe('Brand Preservation Through Type System', () => {
   describe('Step 1: columnType return type', () => {
@@ -33,9 +40,9 @@ describe('Brand Preservation Through Type System', () => {
 
     it('should preserve VariantMarker with different insert/update types', () => {
       const timestampField = columnType(
-        Schema.DateFromSelf,
-        Schema.optional(Schema.DateFromSelf),
-        Schema.DateFromSelf
+        DateFromInput,
+        Schema.optional(DateFromInput),
+        DateFromInput
       );
 
       type TimestampType = Schema.Schema.Type<typeof timestampField>;
@@ -67,7 +74,7 @@ describe('Brand Preservation Through Type System', () => {
     it('should preserve VariantMarker on generated fields', () => {
       const TestModel = Schema.Struct({
         id: columnType(Schema.Number.pipe(Schema.brand('TestId')), Schema.Never, Schema.Never),
-        createdAt: generated(Schema.DateFromSelf),
+        createdAt: generated(DateFromInput),
       });
 
       type ModelType = Schema.Schema.Type<typeof TestModel>;
@@ -105,8 +112,8 @@ describe('Brand Preservation Through Type System', () => {
       const TestModel = Schema.Struct({
         id: columnType(Schema.Number.pipe(Schema.brand('TestId')), Schema.Never, Schema.Never),
         name: Schema.String,
-        createdAt: generated(Schema.DateFromSelf),
-        updatedAt: generated(Schema.DateFromSelf),
+        createdAt: generated(DateFromInput),
+        updatedAt: generated(DateFromInput),
       });
 
       type TestInsert = Insertable<typeof TestModel>;
@@ -130,7 +137,7 @@ describe('Brand Preservation Through Type System', () => {
       id: columnType(Schema.UUID.pipe(Schema.brand('UserId')), Schema.Never, Schema.Never),
       email: Schema.String,
       name: Schema.String,
-      createdAt: generated(Schema.DateFromSelf),
+      createdAt: generated(DateFromInput),
     });
     type User = typeof User;
 
@@ -184,7 +191,7 @@ describe('Brand Preservation Through Type System', () => {
 
     it('should correctly extract insert type from generated field', () => {
       const TestModel = Schema.Struct({
-        createdAt: generated(Schema.DateFromSelf),
+        createdAt: generated(DateFromInput),
       });
 
       type ModelType = Schema.Schema.Type<typeof TestModel>;

src/__tests__/deep-type-instantiation.test.ts

@@ -34,6 +34,7 @@ import type {
 import { describe, it, expectTypeOf } from 'vitest';
 import {
   columnType,
+  DateFromInput,
   generated,
   JsonValue,
   type ColumnType,
@@ -75,19 +76,19 @@ const Seller = Schema.Struct({
   payout_schedule: generated(Schema.String),
   minimum_payout_threshold: generated(Schema.Number),
   verification_fields_needed: generated(Schema.Array(Schema.String)),
-  activated_at: Schema.NullOr(Schema.DateFromSelf),
+  activated_at: Schema.NullOr(DateFromInput),
   banned_reason: Schema.NullOr(Schema.String),
   business_type: Schema.NullOr(Schema.String),
   card_payments_capability: Schema.NullOr(Schema.String),
   flagged_reason: Schema.NullOr(Schema.String),
-  last_verification_attempt: Schema.NullOr(Schema.DateFromSelf),
+  last_verification_attempt: Schema.NullOr(DateFromInput),
   stripe_account_id: Schema.NullOr(Schema.UUID),
-  tos_acceptance_date: Schema.NullOr(Schema.DateFromSelf),
+  tos_acceptance_date: Schema.NullOr(DateFromInput),
   transfers_capability: Schema.NullOr(Schema.String),
-  verification_due_by: Schema.NullOr(Schema.DateFromSelf),
+  verification_due_by: Schema.NullOr(DateFromInput),
   verification_status: Schema.NullOr(Schema.String),
-  created_at: generated(Schema.DateFromSelf),
-  updated_at: generated(Schema.DateFromSelf),
+  created_at: generated(DateFromInput),
+  updated_at: generated(DateFromInput),
 });
 type SellerType = Schema.Schema.Type<typeof Seller>;
 
@@ -110,15 +111,15 @@ const Product = Schema.Struct({
   is_subscription_only: generated(Schema.Boolean),
   content: Schema.NullOr(Schema.String),
   current_version_id: Schema.NullOr(Schema.UUID),
-  end_at: Schema.NullOr(Schema.DateFromSelf),
+  end_at: Schema.NullOr(DateFromInput),
   max_quantity: Schema.NullOr(Schema.Number),
-  start_at: Schema.NullOr(Schema.DateFromSelf),
+  start_at: Schema.NullOr(DateFromInput),
   subcategory_id: Schema.NullOr(Schema.UUID),
   suggested_price: Schema.NullOr(Schema.Number),
   thumbnail: Schema.NullOr(Schema.String),
   category_id: Schema.NullOr(Schema.UUID),
-  created_at: generated(Schema.DateFromSelf),
-  updated_at: generated(Schema.DateFromSelf),
+  created_at: generated(DateFromInput),
+  updated_at: generated(DateFromInput),
 });
 type ProductType = Schema.Schema.Type<typeof Product>;
 
@@ -137,11 +138,11 @@ const Order = Schema.Struct({
   email: Schema.NullOr(Schema.String),
   notes: Schema.NullOr(Schema.String),
   stripe_payment_intent_id: Schema.NullOr(Schema.UUID),
-  completed_at: Schema.NullOr(Schema.DateFromSelf),
-  cancelled_at: Schema.NullOr(Schema.DateFromSelf),
-  refunded_at: Schema.NullOr(Schema.DateFromSelf),
-  created_at: generated(Schema.DateFromSelf),
-  updated_at: generated(Schema.DateFromSelf),
+  completed_at: Schema.NullOr(DateFromInput),
+  cancelled_at: Schema.NullOr(DateFromInput),
+  refunded_at: Schema.NullOr(DateFromInput),
+  created_at: generated(DateFromInput),
+  updated_at: generated(DateFromInput),
 });
 type OrderType = Schema.Schema.Type<typeof Order>;
 
@@ -159,9 +160,9 @@ const Payment = Schema.Struct({
   failure_code: Schema.NullOr(Schema.String),
   failure_message: Schema.NullOr(Schema.String),
   refund_amount: Schema.NullOr(Schema.Number),
-  refunded_at: Schema.NullOr(Schema.DateFromSelf),
-  created_at: generated(Schema.DateFromSelf),
-  updated_at: generated(Schema.DateFromSelf),
+  refunded_at: Schema.NullOr(DateFromInput),
+  created_at: generated(DateFromInput),
+  updated_at: generated(DateFromInput),
 });
 type PaymentType = Schema.Schema.Type<typeof Payment>;
 
@@ -321,8 +322,8 @@ const PaymentWithJson = Schema.Struct({
   last_payment_error: Schema.NullOr(columnType(JsonValue, JsonValue, JsonValue)),
   metadata: Schema.NullOr(columnType(JsonValue, JsonValue, JsonValue)),
   raw_response: columnType(JsonValue, JsonValue, JsonValue),
-  created_at: generated(Schema.DateFromSelf),
-  updated_at: generated(Schema.DateFromSelf),
+  created_at: generated(DateFromInput),
+  updated_at: generated(DateFromInput),
 });
 
 interface JsonTestDB {