feat(typescript-types): Allow inversion of filter in KeyPaths<T, O, F>

packages/typescript-types/src/key-paths.ts

@@ -1,3 +1,8 @@
+import type { If } from './if.js'
+import type { Or } from './or.js'
+import type { And } from './and.js'
+import type { Not } from './not.js'
+import type { IsEmptyString } from './is-empty-string.js'
 import type { Extends } from './extends.js'
 import type { Concat } from './concat.js'
 import type { Assign } from './assign.js'
@@ -20,15 +25,21 @@ interface KeyPaths_DefaultOptions {
 type ExtendsFilter<Obj, Key extends keyof Obj, Filter> =
 	Extends<Obj[Key], Filter> extends false ? false : true
 
-type IncludeElement<Obj, Key extends keyof Obj, Filter> = Obj extends never
+type IncludeElement<Obj, Key extends keyof Obj, Filter, Options extends RequiredOptions> = Obj extends never
 	? false
 	: Obj[Key] extends never
 		? false
 		: unknown extends Obj[Key]
 			? false
-			: ExtendsFilter<Obj, Key, Filter> extends false
+			: Not<
-				? true
+					Or<
-				: false
+						And<ExtendsFilter<Obj, Key, Filter>, Not<Options['invertFilter']>>,
+						And<
+							And<Not<ExtendsFilter<Obj, Key, Filter>>, Options['invertFilter']>,
+							Not<Obj[Key] extends object ? true : false>
+						>
+					>
+				>
 
 type AdaptKeyForOptionals<Obj, Key extends keyof Obj> = Key extends number | string
 	? undefined extends Obj[Key]
@@ -41,6 +52,10 @@ type AdaptKeyForOptionals<Obj, Key extends keyof Obj> = Key extends number | str
 type NonUndefined<Obj> = Obj extends undefined ? never : Obj
 type KeysOf<Obj> = Obj extends undefined ? never : Exclude<keyof Obj, keyof any[]>
 
+type GetCurrentPrefixedKey<Parent extends string, Key extends string, Options extends RequiredOptions> =
+	| Concat<Parent, Key, Options['separator']>
+	| If<Or<Options['leavesOnly'], IsEmptyString<Parent>>, never, Parent>
+
 type KeyPathsOfStringKeys<
 	Obj,
 	Key extends keyof Obj,
@@ -48,9 +63,9 @@ type KeyPathsOfStringKeys<
 	Filter,
 	Parent extends string = ''
 > = Key extends Key
-	? IncludeElement<Obj, Key, Filter> extends true
+	? IncludeElement<Obj, Key, Filter, Options> extends true
 		? Obj[Key] extends NonContainerType
-			? Concat<Parent, AdaptKeyForOptionals<Obj, Key>, Options['separator']>
+			? GetCurrentPrefixedKey<Parent, AdaptKeyForOptionals<Obj, Key>, Options>
 			: KeyPathsOfStringKeys<
 					NonUndefined<Obj[Key]>,
 					KeysOf<Obj[Key]>,

packages/typescript-types/test/key-paths.tst.ts

@@ -9,26 +9,76 @@ interface ExampleObject {
 	undefinedKey: undefined
 	undefinedOptionalKey?: undefined
 	optionalKey?: string
+	objectKey: {
+		name: string
+		age?: number
+	}
+	optionalObjectKey?: {
+		name: string
+		age?: number
+	}
 	arrayKey: [{ name: string; age: number }, 1]
 	optionalArrayKey?: [{ name: string }, { age?: number }]
 }
 
+type KeysWithDefaultSettings =
+	| 'simplevalue'
+	| 'objectKey.name'
+	| 'arrayKey.0.name'
+	| 'arrayKey.0.age'
+	| 'arrayKey.1'
+
+type KeysWithInvertFilterSettings =
+	| 'nullvalue'
+	| 'undefinedKey'
+	| 'undefinedOptionalKey'
+	| 'optionalKey?'
+	| 'objectKey.age?'
+	| 'optionalObjectKey?.age?'
+	| 'optionalArrayKey?.1.age?'
+
+type KeysWithSpecialSeparator =
+	| 'simplevalue'
+	| 'objectKey-name'
+	| 'arrayKey-0-name'
+	| 'arrayKey-0-age'
+	| 'arrayKey-1'
+
 type KeysWhenFilterIsSetToNever =
 	| 'nullvalue'
 	| 'simplevalue'
 	| 'undefinedKey'
 	| 'undefinedOptionalKey'
 	| 'optionalKey?'
+	| 'objectKey.name'
+	| 'objectKey.age?'
+	| 'optionalObjectKey?.name'
+	| 'optionalObjectKey?.age?'
 	| 'arrayKey.0.name'
 	| 'arrayKey.0.age'
 	| 'arrayKey.1'
 	| 'optionalArrayKey?.0.name'
 	| 'optionalArrayKey?.1.age?'
 
+type KeysWithLeavesOnlyDisabled =
+	| 'simplevalue'
+	| 'objectKey'
+	| 'objectKey.name'
+	| 'arrayKey'
+	| 'arrayKey.0'
+	| 'arrayKey.0.name'
+	| 'arrayKey.0.age'
+	| 'arrayKey.1'
+
 // type T = any extends never ? true : false
-// type A = KeyPaths<ExampleObject, {}, never>
+// type A = KeyPaths<ExampleObject, { invertFilter: true }>
-expect<KeyPaths<ExampleObject>>().type.toBe<
+expect<KeyPaths<ExampleObject>>().type.toBe<KeysWithDefaultSettings>()
-	'simplevalue' | 'arrayKey.0.name' | 'arrayKey.0.age' | 'arrayKey.1'
+expect<KeyPaths<ExampleObject, { invertFilter: true }>>().type.toBe<KeysWithInvertFilterSettings>()
->()
+expect<KeyPaths<ExampleObject, { separator: '-' }>>().type.toBe<KeysWithSpecialSeparator>()
+expect<KeyPaths<ExampleObject, { leavesOnly: false }>>().type.toBe<KeysWithLeavesOnlyDisabled>()
+
 expect<KeyPaths<ExampleObject, {}, never>>().type.toBe<KeysWhenFilterIsSetToNever>()
 expect<KeyPaths<ExampleObject, {}, any>>().type.toBeAssignableWith<never>()
+
+expect<KeyPaths<ExampleObject, { invertFilter: true }, never>>().type.toBeAssignableWith<never>()
+expect<KeyPaths<ExampleObject, { invertFilter: true }, any>>().type.toBe<KeysWhenFilterIsSetToNever>()