Keep stale data rendered while a refresh is waiting

Author: RhysSullivan

packages/react/src/lib/async-result.test.ts

@@ -5,14 +5,20 @@ import * as AsyncResult from "effect/unstable/reactivity/AsyncResult";
 import { isAsyncResultLoading } from "./async-result";
 
 describe("isAsyncResultLoading", () => {
-  it("treats initial and waiting async results as loading", () => {
+  it("treats initial and waiting-without-value async results as loading", () => {
     expect(isAsyncResultLoading(AsyncResult.initial())).toBe(true);
     expect(isAsyncResultLoading(AsyncResult.initial(true))).toBe(true);
-    expect(isAsyncResultLoading(AsyncResult.success(["cached"], { waiting: true }))).toBe(true);
+    expect(isAsyncResultLoading(AsyncResult.failure(Cause.fail("boom"), { waiting: true }))).toBe(
+      true,
+    );
   });
 
   it("does not treat settled success or failure as loading", () => {
     expect(isAsyncResultLoading(AsyncResult.success(["ready"]))).toBe(false);
     expect(isAsyncResultLoading(AsyncResult.failure(Cause.fail("boom")))).toBe(false);
   });
+
+  it("keeps stale values rendered while a refresh is waiting", () => {
+    expect(isAsyncResultLoading(AsyncResult.success(["cached"], { waiting: true }))).toBe(false);
+  });
 });

packages/react/src/lib/async-result.ts

@@ -1,5 +1,9 @@
 import * as AsyncResult from "effect/unstable/reactivity/AsyncResult";
+import * as Option from "effect/Option";
 
 export function isAsyncResultLoading<A, E>(result: AsyncResult.AsyncResult<A, E>): boolean {
-  return AsyncResult.isInitial(result) || AsyncResult.isWaiting(result);
+  return (
+    AsyncResult.isInitial(result) ||
+    (AsyncResult.isWaiting(result) && Option.isNone(AsyncResult.value(result)))
+  );
 }