DropDownList: move changes to lookup

Author: anna-shakhova

packages/devextreme/js/__internal/ui/drop_down_editor/m_drop_down_list.ts

@@ -603,6 +603,19 @@ const DropDownList = DropDownEditor.inherit({
     return this._searchValue().toString().length >= this.option('minSearchLength');
   },
 
+  _needClearFilter() {
+    return this._canKeepDataSource() ? false : this._needPassDataSourceToList();
+  },
+
+  _canKeepDataSource() {
+    const isMinSearchLengthExceeded = this._isMinSearchLengthExceeded();
+    return this._dataController.isLoaded()
+            && this.option('showDataBeforeSearch')
+            && this.option('minSearchLength')
+            && !isMinSearchLengthExceeded
+            && !this._isLastMinSearchLengthExceeded;
+  },
+
   _searchValue() {
     return this._input().val() || '';
   },
@@ -662,21 +675,11 @@ const DropDownList = DropDownEditor.inherit({
     }
   },
 
-  _presetListDataSource() {
-    if (this._list && this._shouldRefreshDataSource()) {
-      // this._dataSource.beginLoading();
-      this._setListDataSource();
-      // this._dataSource.endLoading();
-    }
-  },
-
   _searchHandler(e, searchValue) {
     if (this._isTextCompositionInProgress()) {
       return;
     }
 
-    this._presetListDataSource();
-
     if (!this._isMinSearchLengthExceeded()) {
       this._searchCanceled();
       return;
@@ -700,16 +703,7 @@ const DropDownList = DropDownEditor.inherit({
     if (this._needClearFilter()) {
       this._filterDataSource(null);
     }
-  },
-
-  _needClearFilter(): boolean {
-    const isMinSearchLengthExceeded = this._isMinSearchLengthExceeded();
-
-    return this._dataController.isLoaded()
-      && !this.option('showDataBeforeSearch')
-      && !!this.option('minSearchLength')
-      && !isMinSearchLengthExceeded
-      && this._isLastMinSearchLengthExceeded;
+    this._refreshList();
   },
 
   _searchDataSource(searchValue = this._searchValue()) {

packages/devextreme/js/__internal/ui/list/m_list.base.ts

@@ -564,12 +564,6 @@ export const ListBase = CollectionWidget.inherit({
   },
 
   _dataSourceChangedHandler() {
-    const isSearchCompleted = !this._dataSource?.isLoading();
-
-    if (!isSearchCompleted) {
-      return;
-    }
-
     if (!this._shouldAppendItems() && hasWindow()) {
       this._scrollView && this._scrollView.scrollTo(0);
     }

packages/devextreme/js/__internal/ui/m_lookup.ts

@@ -811,6 +811,37 @@ const Lookup = DropDownList.inherit({
     }
   },
 
+  _presetListDataSource() {
+    if (this._list && this._shouldRefreshDataSource()) {
+      const forceLoading = !this._isLastMinSearchLengthExceeded;
+
+      if (forceLoading) {
+        this._dataSource.beginLoading();
+      }
+
+      this._setListDataSource();
+
+      if (forceLoading) {
+        this._dataSource.endLoading();
+      }
+    }
+  },
+
+  _searchHandler() {
+    this._presetListDataSource();
+    this.callBase();
+  },
+
+  _needClearFilter(): boolean {
+    const isMinSearchLengthExceeded = this._isMinSearchLengthExceeded();
+
+    return this._dataController.isLoaded()
+      && !this.option('showDataBeforeSearch')
+      && !!this.option('minSearchLength')
+      && !isMinSearchLengthExceeded
+      && this._isLastMinSearchLengthExceeded;
+  },
+
   _updateActiveDescendant() {
     this.callBase();
 
@@ -987,6 +1018,29 @@ const Lookup = DropDownList.inherit({
     this.callBase();
   },
 
+  _renderList() {
+    this.callBase();
+    this._setListDataSourceChangedHandler();
+  },
+
+  _setListDataSourceChangedHandler() {
+    const defaultHandler = this._list._dataSourceChangedHandler.bind(this._list);
+
+    this._list._dataSourceChangedHandler = this._enrichListDataSourceChangeHandler(defaultHandler);
+  },
+
+  _enrichListDataSourceChangeHandler(defaultHandler) {
+    return (...args) => {
+      const isSearchCompleted = !this._getDataSource()?.isLoading();
+
+      if (!isSearchCompleted) {
+        return;
+      }
+
+      defaultHandler(...args);
+    };
+  },
+
   _clean() {
     this._$fieldWrapper.remove();
     clearTimeout(this._hideOnParentScrollTimer);