Use transaction.commit() if available

.changeset/green-parents-compare.md

@@ -0,0 +1,5 @@
+---
+"@firebase/firestore": patch
+---
+
+On browsers that support IndexedDB V3, we now invoke `transaction.commit()` to speed up data processing.

packages/firestore/src/local/simple_db.ts

@@ -121,6 +121,16 @@ export class SimpleDbTransaction {
     }
   }
 
+  maybeCommit(): void {
+    // If the browser supports V3 IndexedDB, we invoke commit() explicitly to
+    // speed up index DB processing if the event loop remains blocks.
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const maybeV3IndexedDb = this.transaction as any;
+    if (!this.aborted && typeof maybeV3IndexedDb.commit === 'function') {
+      maybeV3IndexedDb.commit();
+    }
+  }
+
   /**
    * Returns a SimpleDbStore<KeyType, ValueType> for the specified store. All
    * operations performed on the SimpleDbStore happen within the context of this
@@ -400,6 +410,10 @@ export class SimpleDb {
           objectStores
         );
         const transactionFnResult = transactionFn(transaction)
+          .next(result => {
+            transaction.maybeCommit();
+            return result;
+          })
           .catch(error => {
             // Abort the transaction if there was an error.
             transaction.abort(error);