chore: rebase

src/internals/functions/Functions.ts

@@ -3,6 +3,10 @@ import { Apply, Fn, MergeArgs, placeholder } from "../core/Core";
 export namespace Functions {
   export type _ = placeholder;
 
+  export interface Identity extends Fn {
+    output: this["args"][0];
+  }
+
   interface PipeableApplyPartial<fn extends Fn, partialArgs extends any[]>
     extends Fn {
     output: Apply<fn, MergeArgs<this["args"], partialArgs>>;
@@ -12,4 +16,22 @@ export namespace Functions {
     fn extends Fn,
     args extends any[]
   > = PipeableApplyPartial<fn, args>;
+
+  type ParametersImpl<fn> = fn extends (...args: infer args) => any
+    ? args
+    : never;
+
+  export interface Parameters extends Fn {
+    output: ParametersImpl<this["args"][0]>;
+  }
+
+  export interface Parameter<N extends number> extends Fn {
+    output: ParametersImpl<this["args"][0]>[N];
+  }
+
+  type ReturnImpl<fn> = fn extends (...args: any[]) => infer ret ? ret : never;
+
+  export interface Return extends Fn {
+    output: ReturnImpl<this["args"][0]>;
+  }
 }

test/HOTScript.test.ts

@@ -3,7 +3,6 @@ import {
   PipeRight,
   Call,
   Fn,
-  IdentityFn,
   Extends,
   Call2,
   Eval,
@@ -23,14 +22,14 @@ describe("HOTScript", () => {
   describe("Functions", () => {
     it("Identity", () => {
       // check primitives
-      type res1 = Call<IdentityFn, string>;
+      type res1 = Call<F.Identity, string>;
       //   ^?
       type tes1 = Expect<Equal<res1, string>>;
-      type res2 = Call<IdentityFn, undefined>;
+      type res2 = Call<F.Identity, undefined>;
       //   ^?
       type tes2 = Expect<Equal<res2, undefined>>;
       // check unions
-      type res3 = Call<IdentityFn, string | number>;
+      type res3 = Call<F.Identity, string | number>;
       //   ^?
       type tes3 = Expect<Equal<res3, string | number>>;
     });

tsconfig.json

@@ -2,6 +2,7 @@
   "compilerOptions": {
     "module": "ESNext",
     "declaration": true,
+    "esModuleInterop": true,
     "target": "ESNext",
     "strict": true,
     "outDir": "dist/"