From f94fc1667024e012eb5233e4c2c6cd35a2b09a51 Mon Sep 17 00:00:00 2001
From: Mark Erikson <mark@isquaredsoftware.com>
Date: Tue, 23 Apr 2024 00:09:12 +0200
Subject: [PATCH] Try speeding up entity adapter by minimizing Immer reads

---
 .../src/entities/sorted_state_adapter.ts      | 53 ++++++++++++++-----
 packages/toolkit/src/entities/utils.ts        | 11 ++--
 2 files changed, 48 insertions(+), 16 deletions(-)

diff --git a/packages/toolkit/src/entities/sorted_state_adapter.ts b/packages/toolkit/src/entities/sorted_state_adapter.ts
index aef9ff20bb..195345cb87 100644
--- a/packages/toolkit/src/entities/sorted_state_adapter.ts
+++ b/packages/toolkit/src/entities/sorted_state_adapter.ts
@@ -65,11 +65,17 @@ export function createSortedStateAdapter<T, Id extends EntityId>(
   function addManyMutably(
     newEntities: readonly T[] | Record<Id, T>,
     state: R,
+    existingIds?: Id[],
   ): void {
     newEntities = ensureEntitiesArray(newEntities)
 
+    const existingKeys = new Set<Id>(
+      existingIds ?? (current(state.ids) as Id[]),
+    )
+
     const models = newEntities.filter(
-      (model) => !(selectIdValue(model, selectId) in state.entities),
+      // (model) => !(selectId(model) in state.entities),
+      (model) => !existingKeys.has(selectIdValue(model, selectId)),
     )
 
     if (models.length !== 0) {
@@ -103,7 +109,7 @@ export function createSortedStateAdapter<T, Id extends EntityId>(
     state.entities = {} as Record<Id, T>
     state.ids = []
 
-    addManyMutably(newEntities, state)
+    addManyMutably(newEntities, state, [])
   }
 
   function updateOneMutably(update: Update<T, Id>, state: R): void {
@@ -153,14 +159,18 @@ export function createSortedStateAdapter<T, Id extends EntityId>(
     newEntities: readonly T[] | Record<Id, T>,
     state: R,
   ): void {
-    const [added, updated] = splitAddedUpdatedEntities<T, Id>(
+    const [added, updated, existingIdsArray] = splitAddedUpdatedEntities<T, Id>(
       newEntities,
       selectId,
       state,
     )
 
-    updateManyMutably(updated, state)
-    addManyMutably(added, state)
+    if (updated.length) {
+      updateManyMutably(updated, state)
+    }
+    if (added.length) {
+      addManyMutably(added, state, existingIdsArray)
+    }
   }
 
   function areArraysEqual(a: readonly unknown[], b: readonly unknown[]) {
@@ -311,10 +321,14 @@ export function createSortedStateAdapter<T, Id extends EntityId>(
     updatedIds,
     replacedIds,
   ) => {
-    const entities = state.entities as Record<Id, T>
-    let ids = state.ids as Id[]
+    const currentEntities = current(state.entities) as Record<Id, T>
+    const currentIds = current(state.ids) as Id[]
+    // const entities = state.entities as Record<Id, T>
+    const stateEntities = state.entities as Record<Id, T>
+    // let ids = state.ids as Id[]
+    let ids = currentIds
     if (replacedIds) {
-      ids = Array.from(new Set(ids))
+      ids = Array.from(new Set(currentIds))
     }
 
     // //let sortedEntities: T[] = []
@@ -335,9 +349,16 @@ export function createSortedStateAdapter<T, Id extends EntityId>(
     //     }
     //   }
     // }
-    let sortedEntities = ids // Array.from(new Set(state.ids as Id[]))
-      .map((id) => entities[id])
-      .filter(Boolean)
+    let sortedEntities: T[] = []
+    for (const id of ids) {
+      const entity = currentEntities[id]
+      if (entity) {
+        sortedEntities.push(entity)
+      }
+    }
+    // let sortedEntities = ids // Array.from(new Set(state.ids as Id[]))
+    //   .map((id) => currentEntities[id])
+    //   .filter(Boolean)
 
     const wasPreviouslyEmpty = sortedEntities.length === 0
 
@@ -356,7 +377,7 @@ export function createSortedStateAdapter<T, Id extends EntityId>(
 
     // Insert/overwrite all new/updated
     for (const item of addedItems) {
-      entities[selectId(item)] = item
+      stateEntities[selectId(item)] = item
       // console.log('Inserting: ', isDraft(item) ? current(item) : item)
       if (!wasPreviouslyEmpty) {
         insert(sortedEntities, item, comparer)
@@ -366,12 +387,18 @@ export function createSortedStateAdapter<T, Id extends EntityId>(
     if (wasPreviouslyEmpty) {
       sortedEntities = addedItems.slice().sort(comparer)
     } else if (updatedIds?.size) {
+      for (const updatedId of updatedIds) {
+        const item: T = currentEntities[updatedId]
+        // const currentIndex = sortedEntities.indexOf(item)
+        // const newIndex = findInsertIndex(sortedEntities, item, comparer)
+        // console.log('Item: ', updatedId, { currentIndex, newIndex })
+      }
       sortedEntities.sort(comparer)
     }
 
     const newSortedIds = sortedEntities.map(selectId)
     // console.log('New sorted IDs: ', newSortedIds)
-    if (!areArraysEqual(state.ids, newSortedIds)) {
+    if (!areArraysEqual(currentIds, newSortedIds)) {
       state.ids = newSortedIds
     }
   }
diff --git a/packages/toolkit/src/entities/utils.ts b/packages/toolkit/src/entities/utils.ts
index 5e3fb92fc1..fce14d586d 100644
--- a/packages/toolkit/src/entities/utils.ts
+++ b/packages/toolkit/src/entities/utils.ts
@@ -1,3 +1,4 @@
+import { current } from 'immer'
 import type {
   IdSelector,
   Update,
@@ -39,19 +40,23 @@ export function splitAddedUpdatedEntities<T, Id extends EntityId>(
   newEntities: readonly T[] | Record<Id, T>,
   selectId: IdSelector<T, Id>,
   state: DraftableEntityState<T, Id>,
-): [T[], Update<T, Id>[]] {
+): [T[], Update<T, Id>[], Id[]] {
   newEntities = ensureEntitiesArray(newEntities)
 
+  const existingIdsArray = current(state.ids) as Id[]
+  const existingIds = new Set<Id>(existingIdsArray)
+
   const added: T[] = []
   const updated: Update<T, Id>[] = []
 
   for (const entity of newEntities) {
     const id = selectIdValue(entity, selectId)
-    if (id in state.entities) {
+    if (existingIds.has(id)) {
+      // if (id in state.entities) {
       updated.push({ id, changes: entity })
     } else {
       added.push(entity)
     }
   }
-  return [added, updated]
+  return [added, updated, existingIdsArray]
 }