add helloWorld

src/helloWorld.test.ts

@@ -0,0 +1,14 @@
+import { describe, expect, it, vi } from "vitest";
+
+import { helloWorld } from "./helloWorld.js";
+
+describe("helloWorld", () => {
+	it("logs 'Hello World!' to the console", () => {
+		const logger = vi.spyOn(console, "log").mockImplementation(() => undefined);
+
+		helloWorld();
+
+		expect(logger).toHaveBeenCalledWith("Hello World!");
+		expect(logger).toHaveBeenCalledTimes(1);
+	});
+});

src/helloWorld.ts

@@ -0,0 +1,3 @@
+export function helloWorld() {
+	console.log("Hello World!");
+}

src/index.ts

@@ -1,2 +1,3 @@
 export * from "./greet.js";
+export * from "./helloWorld.js";
 export * from "./types.js";