Extension work

packages/reffuse/src/ReffuseExtension.ts

@@ -1,10 +1,28 @@
-import type { Effect } from "effect"
-import * as ReffuseContext from "./ReffuseContext.js"
 import * as Reffuse from "./Reffuse.js"
-import type { Simplify } from "effect/Types"
+import type { Merge, StaticType } from "./types.js"
 
 
-const make = <T extends object>(extension: T) =>
-    <R extends typeof Reffuse.Reffuse>(base: R) => {
+const make = <Ext extends object>(extension: Ext) =>
+    <
+        BaseClass extends typeof Reffuse.Reffuse<R>,
+        R,
+    >(
+        base: BaseClass & typeof Reffuse.Reffuse<R>
+    ): (
+        { new(): Merge<InstanceType<BaseClass>, Ext> } &
+        StaticType<BaseClass>
+    ) => {
         const class_ = class extends base {}
+        return class_
     }
+
+
+const cls = make({
+    prout<R>(this: Reffuse.Reffuse<R>) {}
+})(Reffuse.Reffuse)
+
+class Cls extends cls {}
+
+const cls2 = make({
+    aya() {}
+})(cls)

packages/reffuse/src/types.ts

@@ -0,0 +1,21 @@
+/**
+ * Extracts the common keys between two types
+ */
+export type CommonKeys<A, B> = Extract<keyof A, keyof B>
+
+/**
+ * Obtain the static members type of a constructor function type
+ */
+export type StaticType<T extends abstract new (...args: any) => any> = Omit<T, "prototype">
+
+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 Merge<Super, Self> = Omit<Super, CommonKeys<Self, Super>> & Self