feat: Migrate JavaScript to TypeScript

__tests__/get-os.test.ts

@@ -0,0 +1,18 @@
+import getOS from "../src/get-os";
+
+describe("getOS", () => {
+  test("test", () => {
+    expect(getOS("linux")).toBe("Linux");
+    expect(getOS("darwin")).toBe("macOS");
+    expect(getOS("win32")).toBe("Windows");
+  });
+
+  test("test exception", () => {
+    // expect(() => {
+    //   getOS("win32");
+    // }).toThrowError("Windows is not supported");
+    expect(() => {
+      getOS("centos");
+    }).toThrowError("centos is not supported");
+  });
+});