From 626beb61b3100c5e4fd699c946e0e2fed7e24cb6 Mon Sep 17 00:00:00 2001
From: Pierre-Antoine Mills <pierreantoine.urvoy@gmail.com>
Date: Wed, 10 Mar 2021 16:41:22 +0100
Subject: [PATCH] fix(o.paths): dive within arrays and deeper

---
 sources/List/ObjectOf.ts |  4 ++--
 sources/Object/Paths.ts  | 35 +++++++++++++++--------------------
 tests/Object.ts          |  5 ++++-
 3 files changed, 21 insertions(+), 23 deletions(-)

diff --git a/sources/List/ObjectOf.ts b/sources/List/ObjectOf.ts
index 42b679b41..1fbb46850 100644
--- a/sources/List/ObjectOf.ts
+++ b/sources/List/ObjectOf.ts
@@ -12,8 +12,8 @@ import {List} from './List'
  * ```
  */
 export type ObjectOf<O extends List> =
-    O extends List
+    O extends unknown
     ? number extends Length<O> // detect arrays
       ? _Pick<O, number>       // preserves arrays
       : _Omit<O, keyof any[]>  // transforms tuples
-    : O
+    : never
diff --git a/sources/Object/Paths.ts b/sources/Object/Paths.ts
index 288fa9550..878ff0056 100644
--- a/sources/Object/Paths.ts
+++ b/sources/Object/Paths.ts
@@ -1,35 +1,30 @@
-import {OptionalFlat} from '../Object/Optional'
 import {Key} from '../Any/Key'
 import {NonNullableFlat} from '../Object/NonNullable'
 import {Cast} from '../Any/Cast'
 import {List} from '../List/List'
-import {Append} from '../List/Append'
 import {BuiltIn} from '../Misc/BuiltIn'
 import {Primitive} from '../Misc/Primitive'
 import {Length} from '../List/Length'
+import {Keys} from '../Any/Keys'
 
 /**
  * @hidden
  */
-type __Paths<O, Paths extends List<Key> = []> =
-Length<Paths> extends 10 ? Paths : {
-  0: {[K in keyof O]: __Paths<O[K], Append<Paths, K>>}[keyof O]
-  1: {[K in keyof O]: __Paths<O[K], Append<Paths, K>>}[keyof O & number]
-  // It dives deep, and as it dives, it adds the paths to `Paths`
-  2: NonNullableFlat<OptionalFlat<Paths>>
-}[
-    [keyof O] extends [never] ? 2 :
-    O extends BuiltIn | Primitive ? 2 :
-    O extends ReadonlyArray<any> ? 1 : 0
-]
+type UnionOf<A> =
+    A extends List
+    ? A[number]
+    : A[keyof A]
 
 /**
  * @hidden
  */
-export type _Paths<O extends object> =
-    __Paths<O> extends infer X
-    ? Cast<X, List<Key>>
-    : never
+type _Paths<O, P extends List = []> = UnionOf<{
+    [K in keyof O]:
+    O[K] extends BuiltIn | Primitive ? NonNullableFlat<[...P, K?]> :
+    [Keys<O[K]>] extends [never] ? NonNullableFlat<[...P, K?]> :
+    12 extends Length<P> ? NonNullableFlat<[...P, K?]> :
+    _Paths<O[K], [...P, K?]>
+}>
 
 /**
  * Get all the possible paths of `O`
@@ -40,7 +35,7 @@ export type _Paths<O extends object> =
  * ```ts
  * ```
  */
-export type Paths<O extends object> =
-    O extends unknown
-    ? _Paths<O>
+export type Paths<O, P extends List = []> =
+    _Paths<O, P> extends infer X
+    ? Cast<X, List<Key>>
     : never
diff --git a/tests/Object.ts b/tests/Object.ts
index bea40e320..b6ccfb165 100644
--- a/tests/Object.ts
+++ b/tests/Object.ts
@@ -1053,11 +1053,14 @@ type O_PATHS = {
         };
         b: {};
     };
+} | {
+    c: boolean
 };
 
 checks([
     check<O.Paths<{'prop': {a: 1}[]}>, T.NonNullable<['prop'?, number?, 'a'?]>, Test.Pass>(),
-    check<O.Paths<O_PATHS>, T.NonNullable<['a'?, 'a'?] | ['b'?, 'a'?, 'a'?] | ['b'?, 'b'?]>, Test.Pass>(),
+    check<O.Paths<O_PATHS>, T.NonNullable<['a'?, 'a'?] | ['b'?, 'a'?, 'a'?] | ['b'?, 'b'?] | ['c'?]>, Test.Pass>(),
+    check<O.Paths<O[]>, O.Paths<O[]>, Test.Pass>(),
 ])
 
 // ---------------------------------------------------------------------------------------