fixup! perf(core): optimize memory allocation when reconcilling lists

angular · Oct 17, 2023 · 3e1ab2c · 3e1ab2c
1 parent 4b3a64c
commit 3e1ab2c
Showing 1 changed file with 6 additions and 4 deletions.
diff --git a/packages/core/src/render3/list_reconciliation.ts b/packages/core/src/render3/list_reconciliation.ts
@@ -261,7 +261,7 @@ function initLiveItemsInTheFuture<T>(
  */
 export class UniqueValueMultiKeyMap<K, V> {
   private kvMap = new Map<K, V>();
-  private _vMap: Map<V, V>|undefined;
+  private _vMap: Map<V, V>|undefined = undefined;
 
   private get vMap() {
     return this._vMap ??= new Map<V, V>();
@@ -307,9 +307,11 @@ export class UniqueValueMultiKeyMap<K, V> {
   forEach(cb: (v: V, k: K) => void) {
     for (let [key, value] of this.kvMap) {
       cb(value, key);
-      while (this.vMap.has(value)) {
-        value = this.vMap.get(value)!;
-        cb(value, key);
+      if (this._vMap !== undefined) {
+        while (this.vMap.has(value)) {
+          value = this.vMap.get(value)!;
+          cb(value, key);
+        }
       }
     }
   }