feat: Sync to OSS repo

packages/core/src/fn.ts

@@ -0,0 +1,48 @@
+import { z, type ZodType } from 'zod';
+
+// Explicit return type structures capturing the .schema attachment
+export type WrappedFn<Arg1 extends ZodType, Callback extends (...args: any[]) => any> = ((
+	input: z.input<Arg1>
+) => ReturnType<Callback>) & { schema: Arg1 };
+
+export type WrappedDoubleFn<
+	Arg1 extends ZodType,
+	Arg2 extends ZodType,
+	Callback extends (...args: any[]) => any
+> = ((input1: z.input<Arg1>, input2: z.input<Arg2>) => ReturnType<Callback>) & {
+	schemas: [Arg1, Arg2];
+};
+
+// Single Argument Function
+export function fn<Arg1 extends ZodType, Callback extends (arg: z.output<Arg1>) => any>(
+	arg1: Arg1,
+	cb: Callback
+): WrappedFn<Arg1, Callback> {
+	const result = Object.assign(
+		function (input: z.input<Arg1>): ReturnType<Callback> {
+			const parsed = arg1.parse(input);
+			return cb(parsed);
+		},
+		{ schema: arg1 }
+	);
+
+	return result;
+}
+
+// Double Argument Function
+export function doublefn<
+	Arg1 extends ZodType,
+	Arg2 extends ZodType,
+	Callback extends (arg1: z.output<Arg1>, arg2: z.output<Arg2>) => any
+>(arg1: Arg1, arg2: Arg2, cb: Callback): WrappedDoubleFn<Arg1, Arg2, Callback> {
+	const result = Object.assign(
+		function (input: z.input<Arg1>, input2: z.input<Arg2>): ReturnType<Callback> {
+			const parsed = arg1.parse(input);
+			const parsed2 = arg2.parse(input2);
+			return cb(parsed, parsed2);
+		},
+		{ schemas: [arg1, arg2] as [Arg1, Arg2] }
+	);
+
+	return result;
+}