refactor: drop dead query helpers and simplify read deadline (WealthLedger/frontend#141) (#149)

src/shared/api/client.ts

@@ -208,51 +208,50 @@ function parseJson(body: string): unknown {
 }
 
 async function readAttempt(request: Request): Promise<ReadAttempt> {
-	const controller = new AbortController();
-	const failure: { reason?: "abort" | "timeout" } = {};
-
-	const { promise: deadline, reject: rejectDeadline }
-		= Promise.withResolvers<never>();
-
-	const timeout = setTimeout(() => {
-		failure.reason = "timeout";
-		controller.abort();
-		rejectDeadline(abortError());
-	}, GET_DEADLINE_MS);
-
-	const abort = () => {
-		failure.reason = "abort";
-		controller.abort();
-		rejectDeadline(abortError());
-	};
-
-	request.signal.addEventListener("abort", abort, { once: true });
-	const timedRequest = new Request(request, { signal: controller.signal });
+	// Manual timeout (not AbortSignal.timeout) so fake-timer tests can advance it.
+	const timeout = new AbortController();
+	const timer = setTimeout(() => timeout.abort(), GET_DEADLINE_MS);
+	const signal = AbortSignal.any([request.signal, timeout.signal]);
 
 	try {
-		const response = await Promise.race([fetch(timedRequest), deadline]);
-		const body = await Promise.race([response.text(), deadline]);
-		const problem = parseJson(body);
+		// MSW keeps a stalled body readable after abort, so keep the race.
+		const response = await Promise.race([
+			fetch(new Request(request, { signal })),
+			rejectOnAbort(signal),
+		]);
+
+		const body = await Promise.race([response.text(), rejectOnAbort(signal)]);
 
 		return {
-			problem,
+			problem: parseJson(body),
 			reason: "transient",
 			response: new Response(body, response),
 		};
 	}
 	catch (error) {
-		if (failure.reason === "abort") return { reason: "abort" };
-		if (failure.reason === "timeout" || isNetworkFailure(error))
+		if (request.signal.aborted) return { reason: "abort" };
+		// Timeout or network failure: retryable.
+		if (timeout.signal.aborted || isNetworkFailure(error))
 			return { reason: "transient" };
 
 		throw error;
 	}
 	finally {
-		clearTimeout(timeout);
-		request.signal.removeEventListener("abort", abort);
+		clearTimeout(timer);
 	}
 }
 
+function rejectOnAbort(signal: AbortSignal): Promise<never> {
+	return new Promise((_resolve, reject) => {
+		// The signal is either already aborted or one of two parents firing once.
+		signal.addEventListener(
+			"abort",
+			() => reject(abortError()),
+			{ once: true },
+		);
+	});
+}
+
 function retryAfterMs(response: Response): number | undefined {
 	const header = response.headers.get("Retry-After");
 	if (!header) return undefined;