merge concurrent request states

src/use-swr.ts

@@ -54,8 +54,7 @@ export const useSWRHandler = <Data = any, Error = any>(
     STATE_UPDATERS,
     MUTATION_TS,
     MUTATION_END_TS,
-    CONCURRENT_PROMISES,
-    CONCURRENT_PROMISES_TS
+    CONCURRENT_REQUESTS
   ] = SWRGlobalState.get(cache) as GlobalState
 
   // `key` is the identifier of the SWR `data` state, `keyErr` and
@@ -146,8 +145,7 @@ export const useSWRHandler = <Data = any, Error = any>(
 
       // If there is no ongoing concurrent request, or `dedupe` is not set, a
       // new request should be initiated.
-      const shouldStartNewRequest =
-        isUndefined(CONCURRENT_PROMISES[key]) || !opts.dedupe
+      const shouldStartNewRequest = !CONCURRENT_REQUESTS[key] || !opts.dedupe
 
       // Do unmount check for calls:
       // If key has changed during the revalidation, or the component has been
@@ -159,11 +157,10 @@ export const useSWRHandler = <Data = any, Error = any>(
         initialMountedRef.current
 
       const cleanupState = () => {
-        // CONCURRENT_PROMISES_TS[key] might be overridden, check if it's still
-        // the same request before deleting.
-        if (CONCURRENT_PROMISES_TS[key] === startAt) {
-          delete CONCURRENT_PROMISES[key]
-          delete CONCURRENT_PROMISES_TS[key]
+        // Check if it's still the same request before deleting.
+        const requestInfo = CONCURRENT_REQUESTS[key]
+        if (requestInfo && requestInfo[1] === startAt) {
+          delete CONCURRENT_REQUESTS[key]
         }
       }
 
@@ -202,15 +199,14 @@ export const useSWRHandler = <Data = any, Error = any>(
             }, config.loadingTimeout)
           }
 
-          // Start the request and keep the timestamp.
-          CONCURRENT_PROMISES_TS[key] = getTimestamp()
-          CONCURRENT_PROMISES[key] = currentFetcher(...fnArgs)
+          // Start the request and save the timestamp.
+          CONCURRENT_REQUESTS[key] = [currentFetcher(...fnArgs), getTimestamp()]
         }
 
         // Wait until the ongoing request is done. Deduplication is also
         // considered here.
-        startAt = CONCURRENT_PROMISES_TS[key]
-        newData = await CONCURRENT_PROMISES[key]
+        ;[newData, startAt] = CONCURRENT_REQUESTS[key]
+        newData = await newData
 
         if (shouldStartNewRequest) {
           // If the request isn't interrupted, clean it up after the
@@ -223,8 +219,11 @@ export const useSWRHandler = <Data = any, Error = any>(
         //   req1------------------>res1        (current one)
         //        req2---------------->res2
         // the request that fired later will always be kept.
-        // CONCURRENT_PROMISES_TS[key] maybe be `undefined` or a number
-        if (CONCURRENT_PROMISES_TS[key] !== startAt) {
+        // The timestamp maybe be `undefined` or a number
+        if (
+          !CONCURRENT_REQUESTS[key] ||
+          CONCURRENT_REQUESTS[key][1] !== startAt
+        ) {
           if (shouldStartNewRequest) {
             if (isCurrentKeyMounted()) {
               getConfig().onDiscarded(key)

src/utils/broadcast-state.ts

@@ -11,14 +11,8 @@ export const broadcastState: Broadcaster = (
   revalidate,
   populateCache = true
 ) => {
-  const [
-    EVENT_REVALIDATORS,
-    STATE_UPDATERS,
-    ,
-    ,
-    CONCURRENT_PROMISES,
-    CONCURRENT_PROMISES_TS
-  ] = SWRGlobalState.get(cache) as GlobalState
+  const [EVENT_REVALIDATORS, STATE_UPDATERS, , , CONCURRENT_REQUESTS] =
+    SWRGlobalState.get(cache) as GlobalState
   const revalidators = EVENT_REVALIDATORS[key]
   const updaters = STATE_UPDATERS[key] || []
 
@@ -33,8 +27,7 @@ export const broadcastState: Broadcaster = (
   if (revalidate) {
     // Invalidate the key by deleting the concurrent request markers so new
     // requests will not be deduped.
-    delete CONCURRENT_PROMISES[key]
-    delete CONCURRENT_PROMISES_TS[key]
+    delete CONCURRENT_REQUESTS[key]
 
     if (revalidators && revalidators[0]) {
       return revalidators[0](revalidateEvents.MUTATE_EVENT).then(() =>

src/utils/cache.ts

@@ -48,15 +48,7 @@ export const initCache = <Data = any>(
     let unmount = noop
 
     // Update the state if it's new, or the provider has been extended.
-    SWRGlobalState.set(provider, [
-      EVENT_REVALIDATORS,
-      {},
-      {},
-      {},
-      {},
-      {},
-      mutate
-    ])
+    SWRGlobalState.set(provider, [EVENT_REVALIDATORS, {}, {}, {}, {}, mutate])
 
     // This is a new provider, we need to initialize it and setup DOM events
     // listeners for `focus` and `reconnect` actions.
@@ -104,5 +96,5 @@ export const initCache = <Data = any>(
     return [provider, mutate, unmount]
   }
 
-  return [provider, (SWRGlobalState.get(provider) as GlobalState)[6]]
+  return [provider, (SWRGlobalState.get(provider) as GlobalState)[5]]
 }

src/utils/global-state.ts

@@ -10,8 +10,7 @@ export type GlobalState = [
   Record<string, StateUpdateCallback[]>, // STATE_UPDATERS
   Record<string, number>, // MUTATION_TS
   Record<string, number>, // MUTATION_END_TS
-  Record<string, any>, // CONCURRENT_PROMISES
-  Record<string, number>, // CONCURRENT_PROMISES_TS
+  Record<string, [any, number]>, // CONCURRENT_REQUESTS: [data, ts]
   ScopedMutator // Mutator
 ]