Added a 3rd solution to 13-catch-block-problem

src/13-catch-blocks.solution.2.ts

@@ -6,9 +6,7 @@ const tryCatchDemo = (state: "fail" | "succeed") => {
       throw new Error("Failure!");
     }
   } catch (e) {
-    if (e instanceof Error) {
-      return e.message;
-    }
+    return (e as Error).message;
   }
 };
 

src/13-catch-blocks.solution.3.ts

@@ -0,0 +1,17 @@
+import { expect, it } from "vitest";
+
+const tryCatchDemo = (state: "fail" | "succeed") => {
+  try {
+    if (state === "fail") {
+      throw new Error("Failure!");
+    }
+  } catch (e) {
+    if (e instanceof Error) {
+      return e.message;
+    }
+  }
+};
+
+it("Should return the message when it fails", () => {
+  expect(tryCatchDemo("fail")).toEqual("Failure!");
+});