Make IDEs show simple result types

package.json

@@ -1,6 +1,6 @@
 {
   "name": "kysely",
-  "version": "0.23.4",
+  "version": "0.23.5",
   "description": "Type safe SQL query builder",
   "repository": {
     "type": "git",

src/query-builder/delete-query-builder.ts

@@ -21,7 +21,12 @@ import {
 import { ReturningRow } from '../parser/returning-parser.js'
 import { ReferenceExpression } from '../parser/reference-parser.js'
 import { QueryNode } from '../operation-node/query-node.js'
-import { MergePartial, Nullable, SingleResultType } from '../util/type-utils.js'
+import {
+  MergePartial,
+  Nullable,
+  SimplifyResult,
+  SimplifySingleResult,
+} from '../util/type-utils.js'
 import { preventAwait } from '../util/prevent-await.js'
 import { Compilable } from '../util/compilable.js'
 import { QueryExecutor } from '../query-executor/query-executor.js'
@@ -779,7 +784,7 @@ export class DeleteQueryBuilder<DB, TB extends keyof DB, O>
     )
   }
 
-  compile(): CompiledQuery<O> {
+  compile(): CompiledQuery<SimplifyResult<O>> {
     return this.#props.executor.compileQuery(
       this.toOperationNode(),
       this.#props.queryId
@@ -791,7 +796,7 @@ export class DeleteQueryBuilder<DB, TB extends keyof DB, O>
    *
    * Also see the {@link executeTakeFirst} and {@link executeTakeFirstOrThrow} methods.
    */
-  async execute(): Promise<O[]> {
+  async execute(): Promise<SimplifyResult<O>[]> {
     const compiledQuery = this.compile()
     const query = compiledQuery.query as DeleteQueryNode
 
@@ -801,7 +806,7 @@ export class DeleteQueryBuilder<DB, TB extends keyof DB, O>
     )
 
     if (this.#props.executor.adapter.supportsReturning && query.returning) {
-      return result.rows
+      return result.rows as any
     }
 
     return [
@@ -816,9 +821,9 @@ export class DeleteQueryBuilder<DB, TB extends keyof DB, O>
    * Executes the query and returns the first result or undefined if
    * the query returned no result.
    */
-  async executeTakeFirst(): Promise<SingleResultType<O>> {
+  async executeTakeFirst(): Promise<SimplifySingleResult<O>> {
     const [result] = await this.execute()
-    return result as SingleResultType<O>
+    return result as SimplifySingleResult<O>
   }
 
   /**
@@ -831,14 +836,14 @@ export class DeleteQueryBuilder<DB, TB extends keyof DB, O>
    */
   async executeTakeFirstOrThrow(
     errorConstructor: NoResultErrorConstructor = NoResultError
-  ): Promise<O> {
+  ): Promise<SimplifyResult<O>> {
     const result = await this.executeTakeFirst()
 
     if (result === undefined) {
       throw new errorConstructor(this.toOperationNode())
     }
 
-    return result as O
+    return result as SimplifyResult<O>
   }
 
   /**

src/query-builder/insert-query-builder.ts

@@ -13,7 +13,11 @@ import {
 } from '../parser/insert-values-parser.js'
 import { InsertQueryNode } from '../operation-node/insert-query-node.js'
 import { QueryNode } from '../operation-node/query-node.js'
-import { MergePartial, SingleResultType } from '../util/type-utils.js'
+import {
+  MergePartial,
+  SimplifyResult,
+  SimplifySingleResult,
+} from '../util/type-utils.js'
 import { UpdateObject, parseUpdateObject } from '../parser/update-set-parser.js'
 import { preventAwait } from '../util/prevent-await.js'
 import { Compilable } from '../util/compilable.js'
@@ -726,7 +730,7 @@ export class InsertQueryBuilder<DB, TB extends keyof DB, O>
    *
    * Also see the {@link executeTakeFirst} and {@link executeTakeFirstOrThrow} methods.
    */
-  async execute(): Promise<O[]> {
+  async execute(): Promise<SimplifyResult<O>[]> {
     const compiledQuery = this.compile()
     const query = compiledQuery.query as InsertQueryNode
 
@@ -736,7 +740,7 @@ export class InsertQueryBuilder<DB, TB extends keyof DB, O>
     )
 
     if (this.#props.executor.adapter.supportsReturning && query.returning) {
-      return result.rows
+      return result.rows as any
     }
 
     return [
@@ -752,9 +756,9 @@ export class InsertQueryBuilder<DB, TB extends keyof DB, O>
    * Executes the query and returns the first result or undefined if
    * the query returned no result.
    */
-  async executeTakeFirst(): Promise<SingleResultType<O>> {
+  async executeTakeFirst(): Promise<SimplifySingleResult<O>> {
     const [result] = await this.execute()
-    return result as SingleResultType<O>
+    return result as SimplifySingleResult<O>
   }
 
   /**
@@ -767,14 +771,14 @@ export class InsertQueryBuilder<DB, TB extends keyof DB, O>
    */
   async executeTakeFirstOrThrow(
     errorConstructor: NoResultErrorConstructor = NoResultError
-  ): Promise<O> {
+  ): Promise<SimplifyResult<O>> {
     const result = await this.executeTakeFirst()
 
     if (result === undefined) {
       throw new errorConstructor(this.toOperationNode())
     }
 
-    return result as O
+    return result as SimplifyResult<O>
   }
 
   /**

src/query-builder/select-query-builder.ts

@@ -22,7 +22,12 @@ import {
 } from '../parser/reference-parser.js'
 import { SelectQueryNode } from '../operation-node/select-query-node.js'
 import { QueryNode } from '../operation-node/query-node.js'
-import { MergePartial, Nullable, SingleResultType } from '../util/type-utils.js'
+import {
+  MergePartial,
+  Nullable,
+  Simplify,
+  SimplifySingleResult,
+} from '../util/type-utils.js'
 import {
   OrderByDirectionExpression,
   OrderByExpression,
@@ -1791,7 +1796,7 @@ export class SelectQueryBuilder<DB, TB extends keyof DB, O>
     )
   }
 
-  compile(): CompiledQuery<O> {
+  compile(): CompiledQuery<Simplify<O>> {
     return this.#props.executor.compileQuery(
       this.toOperationNode(),
       this.#props.queryId
@@ -1803,7 +1808,7 @@ export class SelectQueryBuilder<DB, TB extends keyof DB, O>
    *
    * Also see the {@link executeTakeFirst} and {@link executeTakeFirstOrThrow} methods.
    */
-  async execute(): Promise<O[]> {
+  async execute(): Promise<Simplify<O>[]> {
     const compiledQuery = this.compile()
 
     const result = await this.#props.executor.executeQuery<O>(
@@ -1818,9 +1823,9 @@ export class SelectQueryBuilder<DB, TB extends keyof DB, O>
    * Executes the query and returns the first result or undefined if
    * the query returned no result.
    */
-  async executeTakeFirst(): Promise<SingleResultType<O>> {
+  async executeTakeFirst(): Promise<SimplifySingleResult<O>> {
     const [result] = await this.execute()
-    return result as SingleResultType<O>
+    return result as SimplifySingleResult<O>
   }
 
   /**
@@ -1833,7 +1838,7 @@ export class SelectQueryBuilder<DB, TB extends keyof DB, O>
    */
   async executeTakeFirstOrThrow(
     errorConstructor: NoResultErrorConstructor = NoResultError
-  ): Promise<O> {
+  ): Promise<Simplify<O>> {
     const result = await this.executeTakeFirst()
 
     if (result === undefined) {

src/query-builder/update-query-builder.ts

@@ -21,7 +21,12 @@ import {
 import { ReturningRow } from '../parser/returning-parser.js'
 import { ReferenceExpression } from '../parser/reference-parser.js'
 import { QueryNode } from '../operation-node/query-node.js'
-import { MergePartial, Nullable, SingleResultType } from '../util/type-utils.js'
+import {
+  MergePartial,
+  Nullable,
+  SimplifyResult,
+  SimplifySingleResult,
+} from '../util/type-utils.js'
 import { UpdateQueryNode } from '../operation-node/update-query-node.js'
 import { UpdateObject, parseUpdateObject } from '../parser/update-set-parser.js'
 import { preventAwait } from '../util/prevent-await.js'
@@ -777,7 +782,7 @@ export class UpdateQueryBuilder<DB, UT extends keyof DB, TB extends keyof DB, O>
     )
   }
 
-  compile(): CompiledQuery<O> {
+  compile(): CompiledQuery<SimplifyResult<O>> {
     return this.#props.executor.compileQuery(
       this.toOperationNode(),
       this.#props.queryId
@@ -789,7 +794,7 @@ export class UpdateQueryBuilder<DB, UT extends keyof DB, TB extends keyof DB, O>
    *
    * Also see the {@link executeTakeFirst} and {@link executeTakeFirstOrThrow} methods.
    */
-  async execute(): Promise<O[]> {
+  async execute(): Promise<SimplifyResult<O>[]> {
     const compiledQuery = this.compile()
     const query = compiledQuery.query as UpdateQueryNode
 
@@ -799,7 +804,7 @@ export class UpdateQueryBuilder<DB, UT extends keyof DB, TB extends keyof DB, O>
     )
 
     if (this.#props.executor.adapter.supportsReturning && query.returning) {
-      return result.rows
+      return result.rows as any
     }
 
     return [
@@ -814,9 +819,9 @@ export class UpdateQueryBuilder<DB, UT extends keyof DB, TB extends keyof DB, O>
    * Executes the query and returns the first result or undefined if
    * the query returned no result.
    */
-  async executeTakeFirst(): Promise<SingleResultType<O>> {
+  async executeTakeFirst(): Promise<SimplifySingleResult<O>> {
     const [result] = await this.execute()
-    return result as SingleResultType<O>
+    return result as SimplifySingleResult<O>
   }
 
   /**
@@ -829,14 +834,14 @@ export class UpdateQueryBuilder<DB, UT extends keyof DB, TB extends keyof DB, O>
    */
   async executeTakeFirstOrThrow(
     errorConstructor: NoResultErrorConstructor = NoResultError
-  ): Promise<O> {
+  ): Promise<SimplifyResult<O>> {
     const result = await this.executeTakeFirst()
 
     if (result === undefined) {
       throw new errorConstructor(this.toOperationNode())
     }
 
-    return result as O
+    return result as SimplifyResult<O>
   }
 
   /**

src/util/type-utils.ts

@@ -122,16 +122,23 @@ export type ArrayItemType<T> = T extends ReadonlyArray<infer I> ? I : never
  */
 export type AnySelectQueryBuilder = SelectQueryBuilder<any, any, any>
 
-/**
- * Given a query output type `O` evaluates to the output type of a `executeTakeFirst` call.
- */
-export type SingleResultType<O> = O extends InsertResult
+export type SimplifySingleResult<O> = O extends InsertResult
   ? O
   : O extends DeleteResult
   ? O
   : O extends UpdateResult
   ? O
-  : O | undefined
+  : Simplify<O> | undefined
+
+export type SimplifyResult<O> = O extends InsertResult
+  ? O
+  : O extends DeleteResult
+  ? O
+  : O extends UpdateResult
+  ? O
+  : Simplify<O>
+
+export type Simplify<T> = { [K in keyof T]: T[K] } & {}
 
 /**
  * Represents a database row whose column names and their types are unknown.

test/typings/test-d/index.test-d.ts

@@ -170,7 +170,7 @@ async function testSelectSingle(db: Kysely<Database>) {
     .select(sql`random() > 0.5`.as(alias))
     .select('first_name')
     .execute()
-  expectType<{ first_name: string } & { [key: string]: unknown }>(r5)
+  expectType<{ first_name: string; [key: string]: unknown }>(r5)
 
   // Subquery
   const [r6] = await qb
@@ -677,7 +677,7 @@ async function testCall(db: Kysely<Database>) {
     .call((qb) => qb.select('name'))
     .execute()
 
-  expectType<{ species: 'dog' | 'cat' } & { name: string }>(r1)
+  expectType<{ species: 'dog' | 'cat'; name: string }>(r1)
 }
 
 async function testIf(db: Kysely<Database>) {
@@ -690,7 +690,7 @@ async function testIf(db: Kysely<Database>) {
     .if(condition, (qb) => qb.select('name'))
     .execute()
 
-  expectType<{ species: 'dog' | 'cat' } & { name?: string }>(r1)
+  expectType<{ species: 'dog' | 'cat'; name?: string }>(r1)
 
   // Conditional returning in delete
   const [r2] = await db
@@ -707,7 +707,7 @@ async function testIf(db: Kysely<Database>) {
     .if(condition, (qb) => qb.returning('last_name'))
     .execute()
 
-  expectType<{ first_name: string } & { last_name?: string | null }>(r3)
+  expectType<{ first_name: string; last_name?: string | null }>(r3)
 
   // Conditional where in delete
   const [r4] = await db
@@ -724,7 +724,7 @@ async function testIf(db: Kysely<Database>) {
     .if(condition, (qb) => qb.where('id', '=', 1))
     .execute()
 
-  expectType<{ first_name: string } & Partial<{}>>(r5)
+  expectType<{ first_name: string }>(r5)
 
   // Conditional returning in update
   const [r6] = await db
@@ -743,7 +743,7 @@ async function testIf(db: Kysely<Database>) {
     .if(condition, (qb) => qb.returning('last_name'))
     .execute()
 
-  expectType<{ first_name: string } & { last_name?: string | null }>(r7)
+  expectType<{ first_name: string; last_name?: string | null }>(r7)
 
   // Conditional where in update
   const [r8] = await db
@@ -762,7 +762,7 @@ async function testIf(db: Kysely<Database>) {
     .if(condition, (qb) => qb.where('id', '=', 1))
     .execute()
 
-  expectType<{ first_name: string } & Partial<{}>>(r9)
+  expectType<{ first_name: string }>(r9)
 
   // Conditional returning in insert
   const [r10] = await db
@@ -781,7 +781,7 @@ async function testIf(db: Kysely<Database>) {
     .if(condition, (qb) => qb.returning('last_name'))
     .execute()
 
-  expectType<{ first_name: string } & { last_name?: string | null }>(r11)
+  expectType<{ first_name: string; last_name?: string | null }>(r11)
 
   // Conditional ingore in insert
   const [r12] = await db
@@ -800,7 +800,7 @@ async function testIf(db: Kysely<Database>) {
     .if(condition, (qb) => qb.ignore())
     .execute()
 
-  expectType<{ first_name: string } & Partial<{}>>(r13)
+  expectType<{ first_name: string }>(r13)
 }
 
 async function testGenericSelect<T extends keyof Database>(