feat: add better message and code for timeout error

src/fetch.ts

@@ -156,10 +156,14 @@ export function createFetch(globalOptions: CreateFetchOptions = {}): $Fetch {
     // TODO: Can we merge signals?
     if (!context.options.signal && context.options.timeout) {
       const controller = new AbortController();
-      abortTimeout = setTimeout(
-        () => controller.abort(),
-        context.options.timeout
-      );
+      abortTimeout = setTimeout(() => {
+        const error = new Error(
+          "[TimeoutError]: The operation was aborted due to timeout"
+        );
+        error.name = "TimeoutError";
+        (error as any).code = 23; // DOMException.TIMEOUT_ERR
+        controller.abort(error);
+      }, context.options.timeout);
       context.options.signal = controller.signal;
     }
 

test/index.test.ts

@@ -337,6 +337,19 @@ describe("ofetch", () => {
     expect(race).to.equal("timeout");
   });
 
+  it("aborting on timeout reason", async () => {
+    await $fetch(getURL("timeout"), {
+      timeout: 100,
+      retry: 0,
+    }).catch((error) => {
+      expect(error.cause.message).to.include(
+        "The operation was aborted due to timeout"
+      );
+      expect(error.cause.name).to.equal("TimeoutError");
+      expect(error.cause.code).to.equal(DOMException.TIMEOUT_ERR);
+    });
+  });
+
   it("deep merges defaultOptions", async () => {
     const _customFetch = $fetch.create({
       query: {