From 94f16a396762d1bcb05e7bc86fdf610bd995dfe8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Valverd=C3=A9?= <me@julienvalver.de>
Date: Mon, 29 Jul 2024 20:35:42 +0200
Subject: [PATCH] 0.1.8 (#9)
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Co-authored-by: Julien Valverdé <julien.valverde@mailo.com>
Reviewed-on: https://git.valverde.cloud/Thilawyn/thilalib/pulls/9
---
 package.json            |  2 +-
 src/Types/CommonKeys.ts |  4 +++
 src/Types/Extend.ts     | 54 +++++++++++++++++++++++++++++++++++++++++
 src/Types/Merge.ts      | 15 ++++++++++++
 src/Types/index.ts      |  3 +++
 src/tests.ts            | 14 +++++++++++
 6 files changed, 91 insertions(+), 1 deletion(-)
 create mode 100644 src/Types/CommonKeys.ts
 create mode 100644 src/Types/Extend.ts
 create mode 100644 src/Types/Merge.ts

diff --git a/package.json b/package.json
index 2b9cd8e..777cd5e 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@thilawyn/thilalib",
-  "version": "0.1.7",
+  "version": "0.1.8",
   "type": "module",
   "files": [
     "./dist"
diff --git a/src/Types/CommonKeys.ts b/src/Types/CommonKeys.ts
new file mode 100644
index 0000000..fc3bef7
--- /dev/null
+++ b/src/Types/CommonKeys.ts
@@ -0,0 +1,4 @@
+/**
+ * Extracts the common keys between two types
+ */
+export type CommonKeys<A, B> = Extract<keyof A, keyof B>
diff --git a/src/Types/Extend.ts b/src/Types/Extend.ts
new file mode 100644
index 0000000..7a9d2cc
--- /dev/null
+++ b/src/Types/Extend.ts
@@ -0,0 +1,54 @@
+import type { CommonKeys } from "./CommonKeys"
+
+
+export type Extend<Super, Self> =
+    Extendable<Super, Self> extends true
+        ? Omit<Super, CommonKeys<Self, Super>> & Self
+        : never
+
+export type Extendable<Super, Self> =
+    Pick<Self, CommonKeys<Self, Super>> extends Pick<Super, CommonKeys<Self, Super>>
+        ? true
+        : false
+
+
+export type ExtendAll<T extends readonly object[]> =
+    T extends readonly [
+        infer Super,
+        infer Self,
+        ...infer Rest extends readonly object[],
+    ]
+        ? Extendable<Super, Self> extends true
+            ? ExtendAll<readonly [Extend<Super, Self>, ...Rest]>
+            : never
+        : T extends readonly [infer Self]
+            ? Self
+            : {}
+
+export type ExtendableAll<T extends readonly object[]> =
+    T extends readonly [
+        infer Super,
+        infer Self,
+        ...infer Rest extends readonly object[],
+    ]
+        ? Extendable<Super, Self> extends true
+            ? ExtendableAll<readonly [Extend<Super, Self>, ...Rest]>
+            : false
+        : true
+
+// export type NonExtendableKeys<T extends readonly object[]> = (
+//     T extends readonly [
+//         infer Super   extends object,
+//         infer Self    extends object,
+//         ...infer Rest extends readonly object[],
+//     ]
+//         ? {[K in keyof Super & keyof Self]: Self[K] extends Super[K]
+//             ? never
+//             : K
+//         }[keyof Super & keyof Self]
+//         | NonExtendableKeys<readonly [
+//             Super & Self,
+//             ...Rest,
+//         ]>
+//         : void
+// )
diff --git a/src/Types/Merge.ts b/src/Types/Merge.ts
new file mode 100644
index 0000000..b38c174
--- /dev/null
+++ b/src/Types/Merge.ts
@@ -0,0 +1,15 @@
+import type { CommonKeys } from "./CommonKeys"
+
+
+export type Merge<Super, Self> = Omit<Super, CommonKeys<Self, Super>> & Self
+
+export type MergeAll<T extends readonly object[]> =
+    T extends readonly [
+        infer Super,
+        infer Self,
+        ...infer Rest extends readonly object[],
+    ]
+        ? MergeAll<readonly [Merge<Super, Self>, ...Rest]>
+        : T extends readonly [infer Self]
+            ? Self
+            : {}
diff --git a/src/Types/index.ts b/src/Types/index.ts
index fc3cf1c..78e48e0 100644
--- a/src/Types/index.ts
+++ b/src/Types/index.ts
@@ -1 +1,4 @@
+export * from "./CommonKeys"
+export * from "./Extend"
+export * from "./Merge"
 export * from "./StaticType"
diff --git a/src/tests.ts b/src/tests.ts
index b61ccba..764e0f2 100644
--- a/src/tests.ts
+++ b/src/tests.ts
@@ -1,7 +1,21 @@
 import { Schema as S } from "@effect/schema"
 import { reaction, runInAction } from "mobx"
+import type { Simplify } from "type-fest"
 import { Jsonifiable, MutableTaggedClass } from "./Schema"
 import { ObservableClass } from "./Schema/MobX"
+import type { ExtendAll } from "./Types"
+
+
+type TestA = {
+    heugneu: string
+    type: "Type1" | "Type2"
+}
+
+type TestB = {
+    type: "Type1"
+}
+
+type Merged = Simplify<ExtendAll<[TestA, TestB]>>
 
 
 class User extends MutableTaggedClass<User>()("User", {