refactor(query-core): improve replaceEqualDeep performance

packages/query-core/src/utils.ts

@@ -245,6 +245,8 @@ export function partialMatchKey(a: any, b: any): boolean {
   return false
 }
 
+const hasOwn = Object.prototype.hasOwnProperty
+
 /**
  * This function returns `a` if `b` is deeply equal.
  * If not, it will replace any deeply equal children of `b` with those of `a`.
@@ -258,37 +260,43 @@ export function replaceEqualDeep(a: any, b: any): any {
 
   const array = isPlainArray(a) && isPlainArray(b)
 
-  if (array || (isPlainObject(a) && isPlainObject(b))) {
-    const aItems = array ? a : Object.keys(a)
-    const aSize = aItems.length
-    const bItems = array ? b : Object.keys(b)
-    const bSize = bItems.length
-    const copy: any = array ? [] : {}
-    const aItemsSet = new Set(aItems)
-
-    let equalItems = 0
-
-    for (let i = 0; i < bSize; i++) {
-      const key = array ? i : bItems[i]
-      if (
-        ((!array && aItemsSet.has(key)) || array) &&
-        a[key] === undefined &&
-        b[key] === undefined
-      ) {
-        copy[key] = undefined
-        equalItems++
-      } else {
-        copy[key] = replaceEqualDeep(a[key], b[key])
-        if (copy[key] === a[key] && a[key] !== undefined) {
-          equalItems++
-        }
-      }
+  if (!array && !(isPlainObject(a) && isPlainObject(b))) return b
+
+  const aItems = array ? a : Object.keys(a)
+  const aSize = aItems.length
+  const bItems = array ? b : Object.keys(b)
+  const bSize = bItems.length
+  const copy: any = array ? new Array(bSize) : {}
+
+  let equalItems = 0
+
+  for (let i = 0; i < bSize; i++) {
+    const key: any = array ? i : bItems[i]
+    const aItem = a[key]
+    const bItem = b[key]
+
+    if (aItem === bItem) {
+      copy[key] = aItem
+      if (array ? i < aSize : hasOwn.call(a, key)) equalItems++
+      continue
+    }
+
+    if (
+      aItem === null ||
+      bItem === null ||
+      typeof aItem !== 'object' ||
+      typeof bItem !== 'object'
+    ) {
+      copy[key] = bItem
+      continue
     }
 
-    return aSize === bSize && equalItems === aSize ? a : copy
+    const v = replaceEqualDeep(aItem, bItem)
+    copy[key] = v
+    if (v === aItem) equalItems++
   }
 
-  return b
+  return aSize === bSize && equalItems === aSize ? a : copy
 }
 
 /**
@@ -311,13 +319,12 @@ export function shallowEqualObjects<T extends Record<string, any>>(
   return true
 }
 
-export function isPlainArray(value: unknown) {
+export function isPlainArray(value: unknown): value is Array<unknown> {
   return Array.isArray(value) && value.length === Object.keys(value).length
 }
 
 // Copied from: https://github.com/jonschlinkert/is-plain-object
-// eslint-disable-next-line @typescript-eslint/no-wrapper-object-types
-export function isPlainObject(o: any): o is Object {
+export function isPlainObject(o: any): o is Record<PropertyKey, unknown> {
   if (!hasObjectPrototype(o)) {
     return false
   }