feat: support narrowing by deep object keys in NarrowPartial (#1667)

Co-authored-by: Igal Klebanov <igalklebanov@gmail.com>

Author: ethanresnick

src/index.ts

@@ -245,18 +245,20 @@ export type {
   DrainOuterGeneric,
   Equals,
   ExtractColumnType,
-  UnknownRow,
-  Simplify,
-  SqlBool,
+  NarrowPartial,
+  NotNull,
   Nullable,
   NumbersWhenDataTypeNotAvailable,
-  NotNull,
   NumericString,
   ShallowDehydrateObject,
   ShallowDehydrateValue,
+  Simplify,
+  SimplifyDeep,
   SimplifyResult,
   SimplifySingleResult,
+  SqlBool,
   StringsWhenDataTypeNotAvailable,
+  UnknownRow,
 } from './util/type-utils.js'
 export * from './util/infer-result.js'
 export { logOnce } from './util/log-once.js'

src/util/type-utils.ts

@@ -1,8 +1,8 @@
-import type { InsertResult } from '../query-builder/insert-result.js'
 import type { DeleteResult } from '../query-builder/delete-result.js'
+import type { InsertResult } from '../query-builder/insert-result.js'
+import type { MergeResult } from '../query-builder/merge-result.js'
 import type { UpdateResult } from '../query-builder/update-result.js'
 import type { KyselyTypeError } from './type-error.js'
-import type { MergeResult } from '../query-builder/merge-result.js'
 
 /**
  * Given a database type and a union of table names in that db, returns
@@ -154,19 +154,25 @@ export type Equals<T, U> =
     ? true
     : false
 
-export type NarrowPartial<O, T> = DrainOuterGeneric<
-  T extends object
-    ? {
-        [K in keyof O & string]: K extends keyof T
-          ? T[K] extends NotNull
-            ? Exclude<O[K], null>
+export type NarrowPartial<O, T> = T extends object
+  ? DrainOuterGeneric<{
+      [K in keyof O & string]: K extends keyof T
+        ? T[K] extends NotNull
+          ? Exclude<O[K], null>
+          : T[K] extends object
+            ? SimplifyDeep<O[K] & NarrowPartial<O[K], T[K]>>
             : T[K] extends O[K]
               ? T[K]
               : KyselyTypeError<`$narrowType() call failed: passed type does not exist in '${K}'s type union`>
-          : O[K]
-      }
-    : never
->
+        : O[K]
+    }>
+  : never
+
+export type SimplifyDeep<T> = T extends object
+  ? T extends Date | RegExp | Map<any, any> | Set<any>
+    ? T
+    : DrainOuterGeneric<{ [K in keyof T]: SimplifyDeep<T[K]> } & {}>
+  : T
 
 /**
  * A type constant for marking a column as not null. Can be used with `$narrowPartial`.

test/composite-ts/index.mts

@@ -12,7 +12,7 @@ export function foo<T extends 'myColumn'>(db: Kysely<DB>, field: T) {
     .selectFrom('MyTable')
     .select(field) // <------- was missing DrainOuterGeneric & ExtractColumnType
     .$narrowType<{}>() // <------- was missing KyselyTypeError
-    .executeTakeFirst() // <------- was missing SimplifySingleResult
+    .executeTakeFirst() // <------- was missing Simplify & children, and NarrowPartial
 }
 
 export function bar<T extends keyof DB['MyTable']>(
@@ -22,7 +22,7 @@ export function bar<T extends keyof DB['MyTable']>(
   return db
     .insertInto('MyTable')
     .values({ myColumn: 'test', anotherColumn: 1 })
-    .returning(columns) // <----- was missing SimplifyResult
+    .returning(columns) // <----- was missing Simplify & children, and NarrowPartial
     .execute()
 }
 

test/composite-ts/package-lock.json

@@ -19,11 +19,11 @@ bench('kysely.with(cte, qc => qc.insertInto(table))', () => {
 
 bench('kysely.with(cte, qc => qc.updateTable(table))', () => {
   return kysely.with('cte', (qc) => qc.updateTable('my_table').returningAll())
-}).types([23993, 'instantiations'])
+}).types([23981, 'instantiations'])
 
 bench('kysely.with(cte, qc => qc.deleteFrom(table))', () => {
   return kysely.with('cte', (qc) => qc.deleteFrom('my_table').returningAll())
-}).types([20729, 'instantiations'])
+}).types([20717, 'instantiations'])
 
 bench('kyselyAny.with(cte, qc => qc.selectFrom(table))', () => {
   return kyselyAny.with('cte', (qc) => qc.selectFrom('my_table').selectAll())
@@ -37,11 +37,11 @@ bench('kyselyAny.with(cte, qc => qc.updateTable(table))', () => {
   return kyselyAny.with('cte', (qc) =>
     qc.updateTable('my_table').returningAll(),
   )
-}).types([23783, 'instantiations'])
+}).types([23771, 'instantiations'])
 
 bench('kyselyAny.with(cte, qc => qc.deleteFrom(table))', () => {
   return kyselyAny.with('cte', (qc) => qc.deleteFrom('my_table').returningAll())
-}).types([20519, 'instantiations'])
+}).types([20507, 'instantiations'])
 
 bench('kysely.with(cte, () => selectQuery)', () => {
   return kysely.with('cte', () => kysely.selectFrom('my_table').selectAll())
@@ -53,11 +53,11 @@ bench('kysely.with(cte, () => insertQuery)', () => {
 
 bench('kysely.with(cte, () => updateQuery)', () => {
   return kysely.with('cte', () => kysely.updateTable('my_table').returningAll())
-}).types([23981, 'instantiations'])
+}).types([23969, 'instantiations'])
 
 bench('kysely.with(cte, () => deleteQuery)', () => {
   return kysely.with('cte', () => kysely.deleteFrom('my_table').returningAll())
-}).types([20717, 'instantiations'])
+}).types([20705, 'instantiations'])
 
 bench('kyselyAny.with(cte, () => selectQuery)', () => {
   return kyselyAny.with('cte', () =>
@@ -75,13 +75,13 @@ bench('kyselyAny.with(cte, () => updateQuery)', () => {
   return kyselyAny.with('cte', () =>
     kyselyAny.updateTable('my_table').returningAll(),
   )
-}).types([23771, 'instantiations'])
+}).types([23759, 'instantiations'])
 
 bench('kyselyAny.with(cte, () => deleteQuery)', () => {
   return kyselyAny.with('cte', () =>
     kyselyAny.deleteFrom('my_table').returningAll(),
   )
-}).types([20507, 'instantiations'])
+}).types([20495, 'instantiations'])
 
 bench('kysely.with(cte, selectQuery)', () => {
   return kysely.with('cte', kysely.selectFrom('my_table').selectAll())
@@ -93,11 +93,11 @@ bench('kysely.with(cte, insertQuery)', () => {
 
 bench('kysely.with(cte, updateQuery)', () => {
   return kysely.with('cte', kysely.updateTable('my_table').returningAll())
-}).types([24025, 'instantiations'])
+}).types([24013, 'instantiations'])
 
 bench('kysely.with(cte, deleteQuery)', () => {
   return kysely.with('cte', kysely.deleteFrom('my_table').returningAll())
-}).types([20762, 'instantiations'])
+}).types([20750, 'instantiations'])
 
 bench('kyselyAny.with(cte, selectQuery)', () => {
   return kyselyAny.with('cte', kyselyAny.selectFrom('my_table').selectAll())
@@ -109,8 +109,8 @@ bench('kyselyAny.with(cte, insertQuery)', () => {
 
 bench('kyselyAny.with(cte, updateQuery)', () => {
   return kyselyAny.with('cte', kyselyAny.updateTable('my_table').returningAll())
-}).types([23815, 'instantiations'])
+}).types([23803, 'instantiations'])
 
 bench('kyselyAny.with(cte, deleteQuery)', () => {
   return kyselyAny.with('cte', kyselyAny.deleteFrom('my_table').returningAll())
-}).types([20552, 'instantiations'])
+}).types([20540, 'instantiations'])

test/ts-benchmarks/with.bench.ts

@@ -80,6 +80,12 @@ export interface PersonMetadata {
     }
     tags: string[]
   }>
+  discriminatedUnionProfile: JSONColumnType<{
+    auth:
+      | { type: 'token'; token: string }
+      | { type: 'session'; session_id: string }
+    tags: string[]
+  }>
   experience: JSONColumnType<
     {
       establishment: string

test/typings/shared.d.ts

@@ -1,3 +1,4 @@
+import { expectError, expectType } from 'tsd'
 import {
   type Expression,
   type ExpressionWrapper,
@@ -9,7 +10,6 @@ import {
   sql,
 } from '../index.js'
 import type { Database, Person } from '../shared.js'
-import { expectType, expectError } from 'tsd'
 
 async function testSelectSingle(db: Kysely<Database>) {
   const qb = db.selectFrom('person')
@@ -115,6 +115,11 @@ async function testSelectSingle(db: Kysely<Database>) {
     .$narrowType<NarrowTarget>()
     .execute()
 
+  expectType<
+    | { callback_url: string; queue_id: null }
+    | { callback_url: null; queue_id: string }
+  >(r15)
+
   // Narrow not null
   const [r16] = await db
     .selectFrom('action')
@@ -134,6 +139,20 @@ async function testSelectSingle(db: Kysely<Database>) {
   expectType<string>(r17.callback_url)
   expectType<string>(r17.queue_id)
 
+  // Narrow discriminated union
+  const [r18] = await db
+    .selectFrom('person_metadata')
+    .select(['discriminatedUnionProfile'])
+    .$narrowType<{ discriminatedUnionProfile: { auth: { type: 'token' } } }>()
+    .execute()
+
+  expectType<{
+    discriminatedUnionProfile: {
+      auth: { type: 'token'; token: string }
+      tags: string[]
+    }
+  }>(r18)
+
   const expr1 = db.selectFrom('person').select('first_name').$asScalar()
   expectType<ExpressionWrapper<Database, 'person', string>>(expr1)