Collection widget live update: fix correctionIndex applying in frameworks and after dataSource is updated at runtime (T1250900)

packages/devextreme/js/__internal/ui/collection/m_collection_widget.live_update.ts

@@ -19,21 +19,15 @@ export default CollectionWidget.inherit({
     });
   },
 
-  ctor() {
-    this.callBase.apply(this, arguments);
-
-    this._customizeStoreLoadOptions = (e) => {
-      const dataController = this._dataController;
-
-      if (dataController.getDataSource() && !this._dataController.isLoaded()) {
-        this._correctionIndex = 0;
-      }
-      if (this._correctionIndex && e.storeLoadOptions) {
-        e.storeLoadOptions.skip += this._correctionIndex;
-      }
-    };
+  _customizeStoreLoadOptions(e) {
+    const dataController = this._dataController;
 
-    this._dataController?.on('customizeStoreLoadOptions', this._customizeStoreLoadOptions);
+    if (dataController.getDataSource() && !this._dataController.isLoaded()) {
+      this._correctionIndex = 0;
+    }
+    if (this._correctionIndex && e.storeLoadOptions) {
+      e.storeLoadOptions.skip += this._correctionIndex;
+    }
   },
 
   reload() {
@@ -44,6 +38,7 @@ export default CollectionWidget.inherit({
     this.callBase();
     this._refreshItemsCache();
     this._correctionIndex = 0;
+    this._subscribeLoadOptionsCustomization(true);
   },
 
   _findItemElementByKey(key) {
@@ -146,7 +141,7 @@ export default CollectionWidget.inherit({
   },
 
   _dispose() {
-    this._dataController.off('customizeStoreLoadOptions', this._customizeStoreLoadOptions);
+    this._subscribeLoadOptionsCustomization(false);
     this.callBase();
   },
 
@@ -242,6 +237,19 @@ export default CollectionWidget.inherit({
     domAdapter.insertElement($container.get(0), $itemFrame.get(0), nextSiblingElement);
   },
 
+  _subscribeLoadOptionsCustomization(enable: boolean): void {
+    if (!this._dataController) {
+      return;
+    }
+
+    if (enable) {
+      this._correctionIndex = 0;
+      this._dataController.on('customizeStoreLoadOptions', this._customizeStoreLoadOptions.bind(this));
+    } else {
+      this._dataController.off('customizeStoreLoadOptions', this._customizeStoreLoadOptions.bind(this));
+    }
+  },
+
   _optionChanged(args) {
     switch (args.name) {
       case 'items': {
@@ -256,7 +264,9 @@ export default CollectionWidget.inherit({
           this.option('items', []);
         }
 
+        this._subscribeLoadOptionsCustomization(false);
         this.callBase(args);
+        this._subscribeLoadOptionsCustomization(true);
         break;
       case 'repaintChangesOnly':
         break;

packages/devextreme/testing/tests/DevExpress.ui/collectionWidgetParts/liveUpdateTests.js

@@ -183,4 +183,58 @@ module('live update', {
         assert.strictEqual($items.first().text(), 'text 0 mark', 'the first item correctly updated');
         assert.strictEqual($items.last().text(), 'text 24 mark', 'the last item correctly updated');
     });
+
+    test('next page items should not be excessive skipped after dataSource runtime change and push remove (T1250900)', function(assert) {
+        const newDataSource = new DataSource({
+            load: () => helper.data.sort((a, b) => a.index - b.index),
+            loadMode: 'raw',
+            pageSize: 2,
+            pushAggregationTimeout: 0,
+            key: 'id'
+        });
+        helper.instance.option('dataSource', newDataSource);
+
+        let items = helper.getItems();
+        assert.strictEqual(items.length, 2, '2 items on the first page');
+        assert.strictEqual(items[0].id, 0, '0 item');
+        assert.strictEqual(items[1].id, 1, '1st item');
+
+        newDataSource.store().push([{ type: 'remove', key: 0 }]);
+
+        items = helper.getItems();
+        assert.strictEqual(items.length, 1, '1 item on the first page after remove');
+        assert.strictEqual(items[0].id, 1, '1 item');
+
+        helper.instance.loadNextPage();
+
+        items = helper.getItems();
+        assert.strictEqual(items.length, 3, '2 pages are loaded');
+        assert.strictEqual(items[0].id, 1, '1 item');
+        assert.strictEqual(items[1].id, 2, '2 item');
+        assert.strictEqual(items[2].id, 3, '3 item');
+    });
+
+    test('dataSource runtime change should be correct even if remove was pushed to the previous dataSource', function(assert) {
+        const data = [...helper.data];
+        helper.store.push([{ type: 'remove', key: 0 }]);
+
+        const newDataSource = new DataSource({
+            load: (e) => data.sort((a, b) => a.index - b.index),
+            loadMode: 'raw',
+            pageSize: 2,
+            pushAggregationTimeout: 0,
+            key: 'id'
+        });
+        helper.instance.option('dataSource', newDataSource);
+
+        let items = helper.getItems();
+        assert.strictEqual(items[0].id, 0, '0 item');
+        assert.strictEqual(items[1].id, 1, '1 item');
+
+        helper.instance.loadNextPage();
+
+        items = helper.getItems();
+        assert.strictEqual(items[2].id, 2, '2 item');
+        assert.strictEqual(items[3].id, 3, '3 item');
+    });
 });