From a317633b37e90111f1c7373b7263d4609bb6580e Mon Sep 17 00:00:00 2001
From: Ahmed Hamed <47536525+AEmad01@users.noreply.github.com>
Date: Mon, 10 Apr 2023 11:39:59 +0200
Subject: [PATCH] perf(useQueries): optimize findMatchingObservers fn in
 queriesObserver for large datasets (#5247)

* perf(useQueries): optimize findMatchingObservers fn in queriesObserver for large datasets

* optimize finding unmatchedObservers in queriesObserver

---------

Co-authored-by: aemad01 <ahmedeamd199824@gmail.com>
---
 packages/query-core/src/queriesObserver.ts | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/packages/query-core/src/queriesObserver.ts b/packages/query-core/src/queriesObserver.ts
index c9fbc5e164..381e444a7d 100644
--- a/packages/query-core/src/queriesObserver.ts
+++ b/packages/query-core/src/queriesObserver.ts
@@ -131,33 +131,35 @@ export class QueriesObserver extends Subscribable<QueriesObserverListener> {
     queries: QueryObserverOptions[],
   ): QueryObserverMatch[] {
     const prevObservers = this.observers
+    const prevObserversMap = new Map(
+      prevObservers.map((observer) => [observer.options.queryHash, observer]),
+    )
+
     const defaultedQueryOptions = queries.map((options) =>
       this.client.defaultQueryOptions(options),
     )
 
     const matchingObservers: QueryObserverMatch[] =
       defaultedQueryOptions.flatMap((defaultedOptions) => {
-        const match = prevObservers.find(
-          (observer) =>
-            observer.options.queryHash === defaultedOptions.queryHash,
-        )
+        const match = prevObserversMap.get(defaultedOptions.queryHash)
         if (match != null) {
           return [{ defaultedQueryOptions: defaultedOptions, observer: match }]
         }
         return []
       })
 
-    const matchedQueryHashes = matchingObservers.map(
-      (match) => match.defaultedQueryOptions.queryHash,
+    const matchedQueryHashes = new Set(
+      matchingObservers.map((match) => match.defaultedQueryOptions.queryHash),
     )
     const unmatchedQueries = defaultedQueryOptions.filter(
-      (defaultedOptions) =>
-        !matchedQueryHashes.includes(defaultedOptions.queryHash),
+      (defaultedOptions) => !matchedQueryHashes.has(defaultedOptions.queryHash),
     )
 
+    const matchingObserversSet = new Set(
+      matchingObservers.map((match) => match.observer),
+    )
     const unmatchedObservers = prevObservers.filter(
-      (prevObserver) =>
-        !matchingObservers.some((match) => match.observer === prevObserver),
+      (prevObserver) => !matchingObserversSet.has(prevObserver),
     )
 
     const getObserver = (options: QueryObserverOptions): QueryObserver => {