From 507583e3b760b5f98d7d10c332ddb856a6f2559f Mon Sep 17 00:00:00 2001
From: sinclair <haydn.developer@gmail.com>
Date: Thu, 23 Nov 2023 02:02:13 +0900
Subject: [PATCH] Reimplement Index Types

---
 examples/index.ts | 18 ++++++++++++------
 src/typebox.ts    | 25 ++++++++++++++++++++-----
 2 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/examples/index.ts b/examples/index.ts
index e75241a79..f682e9b9f 100644
--- a/examples/index.ts
+++ b/examples/index.ts
@@ -21,13 +21,19 @@ import {
 } from '@sinclair/typebox'
 import { TObject, TUnion, UnionToTuple, TInteger, TBigInt, TIntersect, TString, TNumber, TBoolean, TNever, TTuple, UnionType, TRecursive } from '@sinclair/typebox'
 
-const T = Type.Intersect([Type.Object({ x: Type.Optional(Type.Number()) }), Type.Object({ x: Type.Optional(Type.Number()) })])
 
-const S = Type.Intersect([Type.Number(), Type.Object({ x: Type.Number() })])
-
-type A = Static<typeof S>
-
-const I = Type.Index(T, Type.KeyOf(T))
+const I = Type.Intersect([
+  Type.Intersect([
+    Type.Object({ x: Type.String(), y: Type.Literal(1) }),
+    Type.Object({ x: Type.String(), y: Type.Number() })
+  ]), 
+  Type.Intersect([
+    Type.Object({ x: Type.String(), y: Type.Number() }), 
+    Type.Object({ x: Type.String(), y: Type.Union([Type.Literal('A'), Type.Literal('B')]) })
+  ])
+])
+
+const R = Type.Index(I, ['x', 'y'])
 
 // prettier-ignore
 // export type UnionTypeIsOptional<T extends TSchema[]> =
diff --git a/src/typebox.ts b/src/typebox.ts
index 9476d489f..329e82b2e 100644
--- a/src/typebox.ts
+++ b/src/typebox.ts
@@ -99,6 +99,21 @@ export type OptionalUnwrapRest<T extends TSchema[]> =
       ? [OptionalUnwrapType<S>, ...OptionalUnwrapRest<R>] 
       : [L, ...OptionalUnwrapRest<R>]
     :  []
+// ------------------------------------------------------------------
+// DistinctRest
+// ------------------------------------------------------------------
+export type DistinctRestIncludes<T extends TSchema[], C extends TSchema> = 
+  T extends [infer L extends TSchema, ...infer R extends TSchema[]]
+    ? C extends L 
+      ? true 
+      : DistinctRestIncludes<R, C> 
+    : false
+export type DistinctRest<T extends TSchema[], Acc extends TSchema[] = []> = 
+  T extends [infer L extends TSchema, ...infer R extends TSchema[]] 
+    ? DistinctRestIncludes<Acc, L> extends false 
+      ? DistinctRest<R, [...Acc, L]>
+      : DistinctRest<R, [...Acc]>
+    : Acc
 // --------------------------------------------------------------------------
 // IntersectType
 // --------------------------------------------------------------------------
@@ -112,8 +127,8 @@ export type IntersectTypeIsOptional<T extends TSchema[]> =
 // prettier-ignore
 export type IntersectTypeOptional<T extends TSchema[], U extends TSchema[] = OptionalUnwrapRest<T>> = 
   IntersectTypeIsOptional<T> extends true
-    ? TOptional<TIntersect<U>>
-    : TIntersect<U>
+    ? TOptional<TIntersect<DistinctRest<U>>>
+    : TIntersect<DistinctRest<U>>
 // prettier-ignore
 export type IntersectType<T extends TSchema[]> = 
   T extends [] ? TNever : 
@@ -132,8 +147,8 @@ export type UnionTypeIsOptional<T extends TSchema[]> =
 // prettier-ignore
 export type UnionTypeOptional<T extends TSchema[], U extends TSchema[] = OptionalUnwrapRest<T>> = 
   UnionTypeIsOptional<T> extends true
-    ? TOptional<TUnion<U>>
-    : TUnion<U>
+    ? TOptional<TUnion<DistinctRest<U>>>
+    : TUnion<DistinctRest<U>>
 // prettier-ignore
 export type UnionType<T extends TSchema[]> = 
   T extends [] ? TNever : 
@@ -487,7 +502,7 @@ export type TIndexKey<T extends TSchema, K extends PropertyKey, R = TIndexKeyRes
 // prettier-ignore
 export type TIndexKeysResolve<T extends TSchema, K extends PropertyKey[]> =
   K extends [infer L extends PropertyKey, ...infer R extends PropertyKey[]]
-    ? [...TIndexKeyResolve<T, L>, ...TIndexKeysResolve<T, R>]
+    ? [TIndexKey<T, L>, ...TIndexKeysResolve<T, R>]
     : []
 // prettier-ignore
 export type TIndexKeys<T extends TSchema, K extends PropertyKey[], R = TIndexKeysResolve<T, K>> =