From 067d5043b58666a33c0f397af1990988d1f239e7 Mon Sep 17 00:00:00 2001
From: Mark Heimer <mark.heimer@t2informatik.de>
Date: Thu, 2 Feb 2023 10:31:05 +0100
Subject: [PATCH] feat/solution-17: implement solution without type casts

---
 ...-you-say-goodbye-i-say-hello.solution.3.ts | 26 +++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 src/04-generics-advanced/17-you-say-goodbye-i-say-hello.solution.3.ts

diff --git a/src/04-generics-advanced/17-you-say-goodbye-i-say-hello.solution.3.ts b/src/04-generics-advanced/17-you-say-goodbye-i-say-hello.solution.3.ts
new file mode 100644
index 0000000..8a4f181
--- /dev/null
+++ b/src/04-generics-advanced/17-you-say-goodbye-i-say-hello.solution.3.ts
@@ -0,0 +1,26 @@
+import { expect, it } from "vitest";
+import { Equal, Expect } from "../helpers/type-utils";
+
+function youSayGoodbyeISayHello(greeting: 'hello'): 'goodbye'
+function youSayGoodbyeISayHello(greeting: 'goodbye'): 'hello'
+function youSayGoodbyeISayHello<TGreeting extends "hello" | "goodbye">(
+  greeting: TGreeting
+){
+  return greeting === "goodbye" ? "hello" : "goodbye";
+}
+
+it("Should return goodbye when hello is passed in", () => {
+  const result = youSayGoodbyeISayHello("hello");
+
+  type test = [Expect<Equal<typeof result, "goodbye">>];
+
+  expect(result).toEqual("goodbye");
+});
+
+it("Should return hello when goodbye is passed in", () => {
+  const result = youSayGoodbyeISayHello("goodbye");
+
+  type test = [Expect<Equal<typeof result, "hello">>];
+
+  expect(result).toEqual("hello");
+});