feat(typescript-types): Fully rewrite KeyPaths<T,O,F>

Rewrite KeyPaths to eleminate 'Too deep instantiations' error of
TypeScript.

packages/typescript-types/README.md

@@ -18,10 +18,26 @@ The types included in this library are categorized by their purpose.
 [`BuiltIns`]: src/built-ins.ts
 [`NonContainerType`]: src/non-container-type.ts
 
+#### Boolean Operator Types
+
+| Type            | Description                                                                |
+| --------------- | -------------------------------------------------------------------------- |
+| [`And<A, B>`][] | `true` if `A` and `B` (both extend `boolean`) are both `true`.             |
+| [`Not<A>`][]    | `true` if `A` (extends `boolean`) is `false` and vice-versa.               |
+| [`Or<A>`][]     | `true` if either `A` or `B` (both extend `boolean`) is `true`.             |
+| [`Xor<A, B>`][] | `true` if `A` and `B` (both extend `boolean`) are not both `false`/`true`. |
+
+[`And<A, B>`]: src/and.ts
+[`Not<A>`]: src/not.ts
+[`Or<A>`]: src/or.ts
+[`Xor<A, B>`]: src/xor.ts
+
 #### Test Types
 
 | Type                                    | Description                                                                                               |
 | --------------------------------------- | --------------------------------------------------------------------------------------------------------- |
+| [`Extends<A, B>`][]                     | `true` if `A` extends `B`, `false` otherwise[^extends_remark].                                            |
+| [`ExtendsExactly<A, B>`][]              | `true` if `A` extends `B`, `false` otherwise[^extends-exactly_remark].                                    |
 | [`IsAny<T>`][]                          | `true` if `T` is `any`, `false` otherwise (`null`, `undefined` also yield `false`)                        |
 | [`IsNever<T>`][]                        | `true` if `T` is `never`, `false` otherwise (`null`, `undefined`, `any` also yield `false`)               |
 | [`IsUndefined<T>`][]                    | `true` if `T` is `undefined`, `false` otherwise (`null`, `never`, `any` also yield `false`).              |
@@ -30,10 +46,12 @@ The types included in this library are categorized by their purpose.
 | [`IsKeyOf<T, K>`][]                     | `true` if `K` is a key of `T`, `false` otherwise. If `T` is `any`, any `K` but `never` will yield `true`. |
 | [`IsEmptyString<S>`][]                  | `true` if `S` is the empty string `''`, `false` otherwise.[^is-empty-string_remark]                       |
 
-[^if_remark]: If `boolean` is passed as `Test` the return value is a union of both branches, i.e. `TrueBranch | FalseBranch`.
+[^extends_remark]: The result may be `boolean` (aka `true | false`) if `A` or `B` is a union type and the union members evaluate to different boolean results.
 
-[^is-empty-string_remark]: If `T` is `any` will yield `true`, as it is taken to be `any` string.
+[^extends-exactly_remark]: The extends check is done non-distributively in case `A` or `B` is a union type.
 
+[`Extends<A, B>`]: src/extends.ts
+[`ExtendsExactly<A, B>`]: src/extends-exactly.ts
 [`IsAny<T>`]: src/is-any.ts
 [`IsNever<T>`]: src/is-never.ts
 [`IsUndefined<T>`]: src/is-undefined.ts
@@ -70,8 +88,10 @@ The types included in this library are categorized by their purpose.
 
 #### Combination Types
 
-| Type                               | Description                                                                                                             |
-| ---------------------------------- | ----------------------------------------------------------------------------------------------------------------------- |
-| [`Assign<Shape, Defaults, Obj>`][] | Return a type with the structure of `Shape` and value types from `Obj` or `Default` for missing optional keys in `Obj`. |
+| Type                                    | Description                                                                                                             |
+| --------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- |
+| [`Assign<Shape, Defaults, Obj>`][]      | Return a type with the structure of `Shape` and value types from `Obj` or `Default` for missing optional keys in `Obj`. |
+| [`Concat<Prefix, Suffix, Separator>`][] | Concatenate `Prefix` and `Suffix` and - if both are non empty strings - separate them using `Separator`.                |
 
 [`Assign<Shape, Defaults, Obj>`]: src/assign.ts
+[`Concat<Prefix, Suffix, Separator>`]: src/concat.ts

packages/typescript-types/src/and.ts

@@ -0,0 +1,5 @@
+export type And<A extends boolean, B extends boolean> = A extends true
+	? B extends true
+		? true
+		: false
+	: false

packages/typescript-types/src/concat.ts

@@ -0,0 +1,9 @@
+import type { If } from './if.js'
+import type { Or } from './or.js'
+import type { IsEmptyString } from './is-empty-string.js'
+
+export type Concat<Prefix extends string, Suffix extends string, Separator extends string = ''> = If<
+	Or<IsEmptyString<Prefix>, IsEmptyString<Suffix>>,
+	`${Prefix}${Suffix}`,
+	`${Prefix}${Separator}${Suffix}`
+>

packages/typescript-types/src/extends-exactly.ts

@@ -0,0 +1 @@
+export type ExtendsExactly<A, B> = [A] extends [B] ? true : false

packages/typescript-types/src/extends.ts

@@ -0,0 +1 @@
+export type Extends<A, B> = A extends B ? true : false

packages/typescript-types/src/index.ts

@@ -1,5 +1,8 @@
+export type * from './and.js'
 export type * from './assign.js'
 export type * from './built-ins.js'
+export type * from './extends-exactly.js'
+export type * from './extends.js'
 export type * from './get.js'
 export type * from './if.js'
 export type * from './is-any.js'
@@ -14,3 +17,4 @@ export type * from './optional-keys-of.js'
 export type * from './pick-assignable.js'
 export type * from './primitive.js'
 export type * from './simplify.js'
+export type * from './xor.js'

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

@@ -1,55 +1,68 @@
-import type { If } from './if.js'
-import type { IsEmptyString } from './is-empty-string.js'
-import type { IsUndefined } from './is-undefined.js'
-import type { Simplify } from './simplify.js'
+import type { Extends } from './extends.js'
+import type { Concat } from './concat.js'
 import type { Assign } from './assign.js'
+import type { NonContainerType } from './non-container-type.js'
 
-interface KeyPaths_Options {
+export interface KeyPaths_Options {
 	separator?: string
 	leavesOnly?: boolean
 	invertFilter?: boolean
 }
 
+type RequiredOptions = Required<KeyPaths_Options>
+
 interface KeyPaths_DefaultOptions {
 	separator: '.'
 	leavesOnly: true
 	invertFilter: false
 }
 
-type GetPrefixedKey<
-	Parent extends string,
-	Key extends string,
-	Separator extends string
-> = `${If<IsEmptyString<Parent>, '', `${Parent}${Separator}`>}${Key}`
+type ExtendsFilter<Obj, Key extends keyof Obj, Filter> =
+	Extends<Obj[Key], Filter> extends false ? false : true
 
-type PrefixIfNot<Cond, Prefix, T> = If<Cond, T, Prefix | T>
+type IncludeElement<Obj, Key extends keyof Obj, Filter> = Obj extends never
+	? false
+	: Obj[Key] extends never
+		? false
+		: unknown extends Obj[Key]
+			? false
+			: ExtendsFilter<Obj, Key, Filter> extends false
+				? true
+				: false
 
-type KeyPathOf<Obj, Options extends Required<KeyPaths_Options>, Parent extends string, Filter = never> =
-	Obj extends Record<PropertyKey, unknown>
-		? PrefixIfNot<Options['leavesOnly'], Parent, KeyPathsOfStringKeys<Obj, Options, Filter, Parent>>
-		: If<IsUndefined<Obj>, never, Parent>
+type AdaptKeyForOptionals<Obj, Key extends keyof Obj> = Key extends number | string
+	? undefined extends Obj[Key]
+		? Obj[Key] extends undefined
+			? `${Key}`
+			: `${Key}?`
+		: `${Key}`
+	: never
+
+type NonUndefined<Obj> = Obj extends undefined ? never : Obj
+type KeysOf<Obj> = Obj extends undefined ? never : Exclude<keyof Obj, keyof any[]>
 
 type KeyPathsOfStringKeys<
-	Obj extends object,
-	Options extends Required<KeyPaths_Options>,
+	Obj,
+	Key extends keyof Obj,
+	Options extends RequiredOptions,
 	Filter,
 	Parent extends string = ''
-> = {
-	[Key in keyof Obj & string]: Obj[Key] extends Filter
-		? If<
-				Options['invertFilter'],
-				KeyPathOf<Obj[Key], Options, GetPrefixedKey<Parent, Key, Options['separator']>, Filter>,
-				never
-			>
-		: If<
-				Options['invertFilter'],
-				never,
-				KeyPathOf<Obj[Key], Options, GetPrefixedKey<Parent, Key, Options['separator']>, Filter>
-			>
-}[keyof Obj & string]
+> = Key extends Key
+	? IncludeElement<Obj, Key, Filter> extends true
+		? Obj[Key] extends NonContainerType
+			? Concat<Parent, AdaptKeyForOptionals<Obj, Key>, Options['separator']>
+			: KeyPathsOfStringKeys<
+					NonUndefined<Obj[Key]>,
+					KeysOf<Obj[Key]>,
+					Options,
+					Filter,
+					Concat<Parent, AdaptKeyForOptionals<Obj, Key>, Options['separator']>
+				>
+		: never
+	: never
 
 export type KeyPaths<
-	Obj extends object,
+	Obj,
 	Options extends KeyPaths_Options = {},
 	Filter = null | undefined
-> = Simplify<KeyPathsOfStringKeys<Obj, Assign<KeyPaths_Options, KeyPaths_DefaultOptions, Options>, Filter>>
+> = KeyPathsOfStringKeys<Obj, keyof Obj, Assign<KeyPaths_Options, KeyPaths_DefaultOptions, Options>, Filter>

packages/typescript-types/src/not.ts

@@ -0,0 +1 @@
+export type Not<A extends boolean> = A extends true ? false : true

packages/typescript-types/src/or.ts

@@ -0,0 +1 @@
+export type Or<A extends boolean, B extends boolean> = A extends true ? true : B extends true ? true : false

packages/typescript-types/src/xor.ts

@@ -0,0 +1 @@
+export type Xor<A extends boolean, B extends Boolean> = [A] extends [B] ? false : true

packages/typescript-types/test/and.tst.ts

@@ -0,0 +1,7 @@
+import type { And } from '@/and.js'
+import { expect } from 'tstyche'
+
+expect<And<true, true>>().type.toBe<true>()
+expect<And<true, false>>().type.toBe<false>()
+expect<And<false, true>>().type.toBe<false>()
+expect<And<false, false>>().type.toBe<false>()

packages/typescript-types/test/concat.tst.ts

@@ -0,0 +1,8 @@
+import type { Concat } from '@/concat.js'
+import { expect } from 'tstyche'
+
+expect<Concat<'', '', ''>>().type.toBe<''>()
+expect<Concat<'Parent', '', ''>>().type.toBe<'Parent'>()
+expect<Concat<'Parent', 'Child', ''>>().type.toBe<'ParentChild'>()
+expect<Concat<'Parent', 'Child', '.'>>().type.toBe<'Parent.Child'>()
+expect<Concat<'', 'Child', '.'>>().type.toBe<'Child'>()

packages/typescript-types/test/extends-exactly.tst.ts

@@ -0,0 +1,7 @@
+import type { ExtendsExactly } from '@/extends-exactly.js'
+import { expect } from 'tstyche'
+
+expect<ExtendsExactly<true, true>>().type.toBe<true>()
+expect<ExtendsExactly<true, boolean>>().type.toBe<true>()
+expect<ExtendsExactly<boolean, true>>().type.toBe<false>()
+expect<ExtendsExactly<false, true>>().type.toBe<false>()

packages/typescript-types/test/extends.tst.ts

@@ -0,0 +1,10 @@
+import type { Extends } from '@/extends.js'
+import { expect } from 'tstyche'
+
+expect<Extends<true, true>>().type.toBe<true>()
+expect<Extends<true, boolean>>().type.toBe<true>()
+expect<Extends<boolean, true>>().type.toBe<boolean>()
+expect<Extends<false, true>>().type.toBe<false>()
+expect<Extends<false, never>>().type.toBe<false>()
+expect<Extends<null, never>>().type.toBe<false>()
+expect<Extends<undefined, never>>().type.toBe<false>()

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

@@ -4,50 +4,31 @@ import { expect } from 'tstyche'
 interface ExampleObject {
 	nullvalue: null
 	simplevalue: string
-	optionalKey?: {
-		nullvalue: null
-		simplevalue: string
-	}
 	unknownKey: unknown
 	neverKey: never
-	config: {
-		nullvalue: null
-		simplevalue: string
-	}
+	undefinedKey: undefined
+	undefinedOptionalKey?: undefined
+	optionalKey?: string
+	arrayKey: [{ name: string; age: number }, 1]
+	optionalArrayKey?: [{ name: string }, { age?: number }]
 }
 
-type AllKeys =
+type KeysWhenFilterIsSetToNever =
 	| 'nullvalue'
 	| 'simplevalue'
-	| 'optionalKey.nullvalue'
-	| 'optionalKey.simplevalue'
-	| 'unknownKey'
-	| 'config.nullvalue'
-	| 'config.simplevalue'
+	| 'undefinedKey'
+	| 'undefinedOptionalKey'
+	| 'optionalKey?'
+	| 'arrayKey.0.name'
+	| 'arrayKey.0.age'
+	| 'arrayKey.1'
+	| 'optionalArrayKey?.0.name'
+	| 'optionalArrayKey?.1.age?'
 
+// type T = any extends never ? true : false
+// type A = KeyPaths<ExampleObject, {}, never>
 expect<KeyPaths<ExampleObject>>().type.toBe<
-	'simplevalue' | 'optionalKey.simplevalue' | 'unknownKey' | 'config.simplevalue'
+	'simplevalue' | 'arrayKey.0.name' | 'arrayKey.0.age' | 'arrayKey.1'
 >()
-expect<KeyPaths<ExampleObject, {}, any>>().type.toBeAssignableTo<never>()
-expect<KeyPaths<ExampleObject, {}, unknown>>().type.toBeAssignableTo<never>()
-expect<KeyPaths<ExampleObject, {}, never>>().type.toBe<AllKeys>()
-expect<KeyPaths<ExampleObject, { invertFilter: true }, any>>().type.toBe<AllKeys>()
-expect<KeyPaths<ExampleObject, {}, null>>().type.toBe<
-	'simplevalue' | 'optionalKey.simplevalue' | 'unknownKey' | 'config.simplevalue'
->()
-expect<KeyPaths<ExampleObject, {}, string>>().type.toBe<
-	'nullvalue' | 'optionalKey.nullvalue' | 'unknownKey' | 'config.nullvalue'
->()
-expect<KeyPaths<ExampleObject, { separator: '-' }>>().type.toBe<
-	'simplevalue' | 'optionalKey-simplevalue' | 'unknownKey' | 'config-simplevalue'
->()
-expect<KeyPaths<ExampleObject, { leavesOnly: false }>>().type.toBe<
-	'simplevalue' | 'optionalKey' | 'optionalKey.simplevalue' | 'unknownKey' | 'config' | 'config.simplevalue'
->()
-
-expect<KeyPaths<any, {}, any>>().type.toBeAssignableTo<never>()
-expect<KeyPaths<never, {}, any>>().type.toBeAssignableTo<never>()
-expect<KeyPaths<never, {}, never>>().type.toBeAssignableTo<never>()
-
-expect<KeyPaths<any, {}, never>>().type.toBe<unknown>()
-expect<KeyPaths<any, {}, string>>().type.toBeAssignableTo<unknown>()
+expect<KeyPaths<ExampleObject, {}, never>>().type.toBe<KeysWhenFilterIsSetToNever>()
+expect<KeyPaths<ExampleObject, {}, any>>().type.toBeAssignableWith<never>()

packages/typescript-types/test/not.tst.ts

@@ -0,0 +1,5 @@
+import type { Not } from '@/not.js'
+import { expect } from 'tstyche'
+
+expect<Not<true>>().type.toBe<false>()
+expect<Not<false>>().type.toBe<true>()

packages/typescript-types/test/or.tst.ts

@@ -0,0 +1,7 @@
+import type { Or } from '@/or.js'
+import { expect } from 'tstyche'
+
+expect<Or<true, true>>().type.toBe<true>()
+expect<Or<true, false>>().type.toBe<true>()
+expect<Or<false, true>>().type.toBe<true>()
+expect<Or<false, false>>().type.toBe<false>()

packages/typescript-types/test/xor.tst.ts

@@ -0,0 +1,7 @@
+import type { Xor } from '@/xor.js'
+import { expect } from 'tstyche'
+
+expect<Xor<true, true>>().type.toBe<false>()
+expect<Xor<true, false>>().type.toBe<true>()
+expect<Xor<false, true>>().type.toBe<true>()
+expect<Xor<false, false>>().type.toBe<false>()