Calling while a value is being loaded will resolve/replace the pendin…

…g record.
bvaughn · Mar 21, 2023 · 903b1a1 · 903b1a1
1 parent bac7cb9
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diff --git a/packages/suspense/CHANGELOG.md b/packages/suspense/CHANGELOG.md
@@ -1,5 +1,8 @@
 # Changelog
 
+## 0.0.29
+* Edge case bugfix: Calling `cache` while a value is being loaded will resolve/replace the pending record.
+
 ## 0.0.28
 * Add `useImperativeIntervalCacheValue` hook for imperatively loading and subscribing to `createIntervalCache` data.
 * Add `getValue` and `getValueIfCached` methods to `createIntervalCache` type.

diff --git a/packages/suspense/src/cache/createCache.test.ts b/packages/suspense/src/cache/createCache.test.ts
@@ -135,6 +135,23 @@ describe("createCache", () => {
 
       expect(load).not.toHaveBeenCalled();
     });
+
+    it("should resolve an in-progress read", async () => {
+      const wouldReject = cache.readAsync("error");
+
+      expect(cache.getValueIfCached("error")).toBeUndefined();
+      expect(cache.getStatus("error")).toBe(STATUS_PENDING);
+
+      cache.cache("VALUE", "error");
+
+      expect(cache.getValueIfCached("error")).toBe("VALUE");
+      expect(cache.getStatus("error")).toBe(STATUS_RESOLVED);
+
+      await wouldReject;
+
+      expect(cache.getValueIfCached("error")).toBe("VALUE");
+      expect(cache.getStatus("error")).toBe(STATUS_RESOLVED);
+    });
   });
 
   describe("evict", () => {

diff --git a/packages/suspense/src/cache/createCache.ts b/packages/suspense/src/cache/createCache.ts
@@ -7,7 +7,6 @@ import {
   CacheMap,
   PendingRecord,
   Record,
-  ResolvedRecord,
   Status,
   StatusCallback,
   UnsubscribeCallback,
@@ -142,9 +141,27 @@ export function createCache<Params extends Array<any>, Value>(
       createPendingMutationRecordMap
     );
 
-    const record: ResolvedRecord<Value> = createResolvedRecord(value);
+    let record: Record<Value> | undefined = getRecord(...params);
+    if (record != null) {
+      if (isPendingRecord(record)) {
+        debugLogInDev("cache()", params, "Update pending record to:", value);
 
-    debugLogInDev("cache()", params, value);
+        const { abortController, deferred } = record.data;
+
+        abortController.abort();
+
+        updateRecordToResolved(record, value);
+
+        // Don't leave any pending request hanging
+        deferred.resolve(value);
+
+        return;
+      }
+    }
+
+    debugLogInDev("cache()", params, "Create new resolved record with:", value);
+
+    record = createResolvedRecord<Value>(value);
 
     recordMap.set(cacheKey, record);
     pendingMutationRecordMap.set(cacheKey, record);
@@ -193,14 +210,22 @@ export function createCache<Params extends Array<any>, Value>(
     subscriberMap.clear();
   }
 
+  function getRecord(...params: Params): Record<Value> | undefined {
+    const cacheKey = getKey(params);
+    const pendingMutationRecordMap = getCacheForType(
+      createPendingMutationRecordMap
+    );
+
+    return pendingMutationRecordMap.get(cacheKey) ?? recordMap.get(cacheKey);
+  }
+
   function getOrCreateRecord(...params: Params): Record<Value> {
     const cacheKey = getKey(params);
     const pendingMutationRecordMap = getCacheForType(
       createPendingMutationRecordMap
     );
 
-    let record =
-      pendingMutationRecordMap.get(cacheKey) ?? recordMap.get(cacheKey);
+    let record = getRecord(...params);
     if (record == null) {
       debugLogInDev(
         "getOrCreateRecord(): record not found. creating record...",