diff --git a/packages/devextreme-angular/src/ui/pivot-grid-field-chooser/index.ts b/packages/devextreme-angular/src/ui/pivot-grid-field-chooser/index.ts
index a79dc8acc058..f9ee9e4275ef 100644
--- a/packages/devextreme-angular/src/ui/pivot-grid-field-chooser/index.ts
+++ b/packages/devextreme-angular/src/ui/pivot-grid-field-chooser/index.ts
@@ -282,10 +282,10 @@ export class DxPivotGridFieldChooserComponent extends DxComponent implements OnD
     
      */
     @Input()
-    get state(): any {
+    get state(): any | undefined {
         return this._getOption('state');
     }
-    set state(value: any) {
+    set state(value: any | undefined) {
         this._setOption('state', value);
     }
 
@@ -498,7 +498,7 @@ export class DxPivotGridFieldChooserComponent extends DxComponent implements OnD
      * This member supports the internal infrastructure and is not intended to be used directly from your code.
     
      */
-    @Output() stateChange: EventEmitter<any>;
+    @Output() stateChange: EventEmitter<any | undefined>;
 
     /**
     
diff --git a/packages/devextreme-angular/src/ui/pivot-grid/index.ts b/packages/devextreme-angular/src/ui/pivot-grid/index.ts
index 79febda6a5fb..3ae22922c3b9 100644
--- a/packages/devextreme-angular/src/ui/pivot-grid/index.ts
+++ b/packages/devextreme-angular/src/ui/pivot-grid/index.ts
@@ -426,10 +426,10 @@ export class DxPivotGridComponent extends DxComponent implements OnDestroy, OnCh
     
      */
     @Input()
-    get stateStoring(): { customLoad?: Function, customSave?: ((state: any) => void), enabled?: boolean, savingTimeout?: number, storageKey?: string, type?: StateStoreType } {
+    get stateStoring(): { customLoad?: Function, customSave?: ((state: any) => void), enabled?: boolean, savingTimeout?: number, storageKey?: string | undefined, type?: StateStoreType } {
         return this._getOption('stateStoring');
     }
-    set stateStoring(value: { customLoad?: Function, customSave?: ((state: any) => void), enabled?: boolean, savingTimeout?: number, storageKey?: string, type?: StateStoreType }) {
+    set stateStoring(value: { customLoad?: Function, customSave?: ((state: any) => void), enabled?: boolean, savingTimeout?: number, storageKey?: string | undefined, type?: StateStoreType }) {
         this._setOption('stateStoring', value);
     }
 
@@ -749,7 +749,7 @@ export class DxPivotGridComponent extends DxComponent implements OnDestroy, OnCh
      * This member supports the internal infrastructure and is not intended to be used directly from your code.
     
      */
-    @Output() stateStoringChange: EventEmitter<{ customLoad?: Function, customSave?: ((state: any) => void), enabled?: boolean, savingTimeout?: number, storageKey?: string, type?: StateStoreType }>;
+    @Output() stateStoringChange: EventEmitter<{ customLoad?: Function, customSave?: ((state: any) => void), enabled?: boolean, savingTimeout?: number, storageKey?: string | undefined, type?: StateStoreType }>;
 
     /**
     
diff --git a/packages/devextreme-angular/src/ui/pivot-grid/nested/state-storing.ts b/packages/devextreme-angular/src/ui/pivot-grid/nested/state-storing.ts
index 52dceee0db61..1e7e91aed8ac 100644
--- a/packages/devextreme-angular/src/ui/pivot-grid/nested/state-storing.ts
+++ b/packages/devextreme-angular/src/ui/pivot-grid/nested/state-storing.ts
@@ -64,10 +64,10 @@ export class DxoPivotGridStateStoringComponent extends NestedOption implements O
     }
 
     @Input()
-    get storageKey(): string {
+    get storageKey(): string | undefined {
         return this._getOption('storageKey');
     }
-    set storageKey(value: string) {
+    set storageKey(value: string | undefined) {
         this._setOption('storageKey', value);
     }
 
diff --git a/packages/devextreme-react/src/pivot-grid-field-chooser.ts b/packages/devextreme-react/src/pivot-grid-field-chooser.ts
index 10addf0198ce..7ec1a436e21b 100644
--- a/packages/devextreme-react/src/pivot-grid-field-chooser.ts
+++ b/packages/devextreme-react/src/pivot-grid-field-chooser.ts
@@ -18,7 +18,7 @@ type ReplaceFieldTypes<TSource, TReplacement> = {
 
 type IPivotGridFieldChooserOptionsNarrowedEvents = {
   onContentReady?: ((e: ContentReadyEvent) => void);
-  onContextMenuPreparing?: ((e: ContextMenuPreparingEvent) => void);
+  onContextMenuPreparing?: ((e: ContextMenuPreparingEvent) => void) | undefined;
   onDisposing?: ((e: DisposingEvent) => void);
   onInitialized?: ((e: InitializedEvent) => void);
 }
diff --git a/packages/devextreme-react/src/pivot-grid.ts b/packages/devextreme-react/src/pivot-grid.ts
index ff90ffbd7abb..b66e15851b7c 100644
--- a/packages/devextreme-react/src/pivot-grid.ts
+++ b/packages/devextreme-react/src/pivot-grid.ts
@@ -17,12 +17,12 @@ type ReplaceFieldTypes<TSource, TReplacement> = {
 }
 
 type IPivotGridOptionsNarrowedEvents = {
-  onCellClick?: ((e: CellClickEvent) => void);
-  onCellPrepared?: ((e: CellPreparedEvent) => void);
+  onCellClick?: ((e: CellClickEvent) => void) | undefined;
+  onCellPrepared?: ((e: CellPreparedEvent) => void) | undefined;
   onContentReady?: ((e: ContentReadyEvent) => void);
-  onContextMenuPreparing?: ((e: ContextMenuPreparingEvent) => void);
+  onContextMenuPreparing?: ((e: ContextMenuPreparingEvent) => void) | undefined;
   onDisposing?: ((e: DisposingEvent) => void);
-  onExporting?: ((e: ExportingEvent) => void);
+  onExporting?: ((e: ExportingEvent) => void) | undefined;
   onInitialized?: ((e: InitializedEvent) => void);
 }
 
@@ -358,7 +358,7 @@ type IStateStoringProps = React.PropsWithChildren<{
   customSave?: ((state: any) => void);
   enabled?: boolean;
   savingTimeout?: number;
-  storageKey?: string;
+  storageKey?: string | undefined;
   type?: StateStoreType;
 }>
 const _componentStateStoring = (props: IStateStoringProps) => {
diff --git a/packages/devextreme-react/src/scheduler.ts b/packages/devextreme-react/src/scheduler.ts
index 978ea1be3715..6b2c9a7ad88e 100644
--- a/packages/devextreme-react/src/scheduler.ts
+++ b/packages/devextreme-react/src/scheduler.ts
@@ -33,18 +33,18 @@ type ReplaceFieldTypes<TSource, TReplacement> = {
 }
 
 type ISchedulerOptionsNarrowedEvents = {
-  onAppointmentAdded?: ((e: AppointmentAddedEvent) => void);
-  onAppointmentAdding?: ((e: AppointmentAddingEvent) => void);
+  onAppointmentAdded?: ((e: AppointmentAddedEvent) => void) | undefined;
+  onAppointmentAdding?: ((e: AppointmentAddingEvent) => void) | undefined;
   onAppointmentClick?: ((e: AppointmentClickEvent) => void);
   onAppointmentContextMenu?: ((e: AppointmentContextMenuEvent) => void);
   onAppointmentDblClick?: ((e: AppointmentDblClickEvent) => void);
-  onAppointmentDeleted?: ((e: AppointmentDeletedEvent) => void);
-  onAppointmentDeleting?: ((e: AppointmentDeletingEvent) => void);
-  onAppointmentFormOpening?: ((e: AppointmentFormOpeningEvent) => void);
-  onAppointmentRendered?: ((e: AppointmentRenderedEvent) => void);
-  onAppointmentTooltipShowing?: ((e: AppointmentTooltipShowingEvent) => void);
-  onAppointmentUpdated?: ((e: AppointmentUpdatedEvent) => void);
-  onAppointmentUpdating?: ((e: AppointmentUpdatingEvent) => void);
+  onAppointmentDeleted?: ((e: AppointmentDeletedEvent) => void) | undefined;
+  onAppointmentDeleting?: ((e: AppointmentDeletingEvent) => void) | undefined;
+  onAppointmentFormOpening?: ((e: AppointmentFormOpeningEvent) => void) | undefined;
+  onAppointmentRendered?: ((e: AppointmentRenderedEvent) => void) | undefined;
+  onAppointmentTooltipShowing?: ((e: AppointmentTooltipShowingEvent) => void) | undefined;
+  onAppointmentUpdated?: ((e: AppointmentUpdatedEvent) => void) | undefined;
+  onAppointmentUpdating?: ((e: AppointmentUpdatingEvent) => void) | undefined;
   onCellClick?: ((e: CellClickEvent) => void);
   onCellContextMenu?: ((e: CellContextMenuEvent) => void);
   onContentReady?: ((e: ContentReadyEvent) => void);
diff --git a/packages/devextreme/js/__internal/grids/pivot_grid/field_chooser/m_field_chooser.ts b/packages/devextreme/js/__internal/grids/pivot_grid/field_chooser/m_field_chooser.ts
index bf0bb3312ec2..3286d083323c 100644
--- a/packages/devextreme/js/__internal/grids/pivot_grid/field_chooser/m_field_chooser.ts
+++ b/packages/devextreme/js/__internal/grids/pivot_grid/field_chooser/m_field_chooser.ts
@@ -97,7 +97,7 @@ export class FieldChooser extends FieldChooserBase {
         layout: 0,
         dataSource: null,
         encodeHtml: true,
-        onContextMenuPreparing: null,
+        onContextMenuPreparing: undefined,
         allowSearch: false,
         searchTimeout: 500,
         texts: {
diff --git a/packages/devextreme/js/__internal/grids/pivot_grid/field_chooser/m_field_chooser_base.ts b/packages/devextreme/js/__internal/grids/pivot_grid/field_chooser/m_field_chooser_base.ts
index 3323acb54ba1..a6ad73994a55 100644
--- a/packages/devextreme/js/__internal/grids/pivot_grid/field_chooser/m_field_chooser_base.ts
+++ b/packages/devextreme/js/__internal/grids/pivot_grid/field_chooser/m_field_chooser_base.ts
@@ -103,7 +103,7 @@ export class FieldChooserBase extends mixinWidget {
       ...{
         allowFieldDragging: true,
         applyChangesMode: 'instantly',
-        state: null,
+        state: undefined,
         headerFilter: {
           width: 252,
           height: 325,
diff --git a/packages/devextreme/js/__internal/grids/pivot_grid/m_widget.ts b/packages/devextreme/js/__internal/grids/pivot_grid/m_widget.ts
index 725e2b9b55a6..eb18b762bd86 100644
--- a/packages/devextreme/js/__internal/grids/pivot_grid/m_widget.ts
+++ b/packages/devextreme/js/__internal/grids/pivot_grid/m_widget.ts
@@ -194,7 +194,7 @@ class PivotGrid extends Widget {
         height: 600,
         applyChangesMode: 'instantly',
       },
-      onContextMenuPreparing: null,
+      onContextMenuPreparing: undefined,
       allowSorting: false,
       allowSortingBySummary: false,
       allowFiltering: false,
@@ -251,13 +251,13 @@ class PivotGrid extends Widget {
         exportToExcel: localizationMessage.format('dxDataGrid-exportToExcel'),
         dataNotAvailable: localizationMessage.format('dxPivotGrid-dataNotAvailable'),
       },
-      onCellClick: null,
-      onCellPrepared: null,
+      onCellClick: undefined,
+      onCellPrepared: undefined,
       showBorders: false,
 
       stateStoring: {
         enabled: false,
-        storageKey: null,
+        storageKey: undefined,
         type: 'localStorage',
         customLoad: null,
         customSave: null,
@@ -266,7 +266,7 @@ class PivotGrid extends Widget {
 
       onExpandValueChanging: null,
       renderCellCountLimit: 20000,
-      onExporting: null,
+      onExporting: undefined,
       headerFilter: {
         width: 252,
         height: 325,
diff --git a/packages/devextreme/js/ui/pivot_grid.d.ts b/packages/devextreme/js/ui/pivot_grid.d.ts
index 15f4c7a7e798..0f4530d96ae1 100644
--- a/packages/devextreme/js/ui/pivot_grid.d.ts
+++ b/packages/devextreme/js/ui/pivot_grid.d.ts
@@ -516,35 +516,35 @@ export interface dxPivotGridOptions extends WidgetOptions<dxPivotGrid> {
     /**
      * @docid
      * @type_function_param1 e:{ui/pivot_grid:CellClickEvent}
-     * @default null
+     * @default undefined
      * @action
      * @public
      */
-    onCellClick?: ((e: CellClickEvent) => void);
+    onCellClick?: ((e: CellClickEvent) => void) | undefined;
     /**
      * @docid
      * @type_function_param1 e:{ui/pivot_grid:CellPreparedEvent}
-     * @default null
+     * @default undefined
      * @action
      * @public
      */
-    onCellPrepared?: ((e: CellPreparedEvent) => void);
+    onCellPrepared?: ((e: CellPreparedEvent) => void) | undefined;
     /**
      * @docid
      * @type_function_param1 e:{ui/pivot_grid:ContextMenuPreparingEvent}
-     * @default null
+     * @default undefined
      * @action
      * @public
      */
-    onContextMenuPreparing?: ((e: ContextMenuPreparingEvent) => void);
+    onContextMenuPreparing?: ((e: ContextMenuPreparingEvent) => void) | undefined;
     /**
      * @docid
      * @type_function_param1 e:{ui/pivot_grid:ExportingEvent}
-     * @default null
+     * @default undefined
      * @action
      * @public
      */
-    onExporting?: ((e: ExportingEvent) => void);
+    onExporting?: ((e: ExportingEvent) => void) | undefined;
     /**
      * @docid
      * @default "standard"
@@ -631,9 +631,9 @@ export interface dxPivotGridOptions extends WidgetOptions<dxPivotGrid> {
       savingTimeout?: number;
       /**
        * @docid
-       * @default null
+       * @default undefined
        */
-      storageKey?: string;
+      storageKey?: string | undefined;
       /**
        * @docid
        * @default "localStorage"
diff --git a/packages/devextreme/js/ui/pivot_grid/data_source.d.ts b/packages/devextreme/js/ui/pivot_grid/data_source.d.ts
index f6cb506ead28..d336a9d855c1 100644
--- a/packages/devextreme/js/ui/pivot_grid/data_source.d.ts
+++ b/packages/devextreme/js/ui/pivot_grid/data_source.d.ts
@@ -173,7 +173,7 @@ export interface PivotGridDataSourceOptions {
      * @default undefined
      * @public
      */
-    fields?: Array<Field>;
+    fields?: Array<Field> | undefined;
     /**
      * @docid
      * @type Filter expression
@@ -293,7 +293,6 @@ export interface PivotGridDataSourceField {
     area?: PivotGridArea | undefined;
     /**
      * @docid PivotGridDataSourceOptions.fields.areaIndex
-     * @default undefined
      * @public
      */
     areaIndex?: number;
@@ -304,13 +303,11 @@ export interface PivotGridDataSourceField {
     calculateCustomSummary?: ((options: { summaryProcess?: string; value?: any; totalValue?: any }) => void);
     /**
      * @docid PivotGridDataSourceOptions.fields.calculateSummaryValue
-     * @default undefined
      * @public
      */
     calculateSummaryValue?: ((e: dxPivotGridSummaryCell) => number | null);
     /**
      * @docid PivotGridDataSourceOptions.fields.caption
-     * @default undefined
      * @public
      */
     caption?: string;
@@ -321,19 +318,16 @@ export interface PivotGridDataSourceField {
     customizeText?: ((cellInfo: { value?: string | number | Date; valueText?: string }) => string);
     /**
      * @docid PivotGridDataSourceOptions.fields.dataField
-     * @default undefined
      * @public
      */
     dataField?: string;
     /**
      * @docid PivotGridDataSourceOptions.fields.dataType
-     * @default undefined
      * @public
      */
     dataType?: PivotGridDataType;
     /**
      * @docid PivotGridDataSourceOptions.fields.displayFolder
-     * @default undefined
      * @public
      */
     displayFolder?: string;
@@ -351,7 +345,6 @@ export interface PivotGridDataSourceField {
     filterType?: FilterType;
     /**
      * @docid PivotGridDataSourceOptions.fields.filterValues
-     * @default undefined
      * @public
      */
     filterValues?: Array<any>;
@@ -363,19 +356,16 @@ export interface PivotGridDataSourceField {
     format?: Format;
     /**
      * @docid PivotGridDataSourceOptions.fields.groupIndex
-     * @default undefined
      * @public
      */
     groupIndex?: number;
     /**
      * @docid PivotGridDataSourceOptions.fields.groupInterval
-     * @default undefined
      * @public
      */
     groupInterval?: PivotGridGroupInterval | number;
     /**
      * @docid PivotGridDataSourceOptions.fields.groupName
-     * @default undefined
      * @public
      */
     groupName?: string;
@@ -399,26 +389,22 @@ export interface PivotGridDataSourceField {
     };
     /**
      * @docid PivotGridDataSourceOptions.fields.isMeasure
-     * @default undefined
      * @public
      */
     isMeasure?: boolean;
     /**
      * @docid PivotGridDataSourceOptions.fields.name
-     * @default undefined
      * @public
      */
     name?: string;
     /**
      * @docid PivotGridDataSourceOptions.fields.runningTotal
-     * @default undefined
      * @public
      */
     runningTotal?: PivotGridRunningTotalMode;
     /**
      * @docid PivotGridDataSourceOptions.fields.selector
      * @type function(data)
-     * @default undefined
      * @public
      */
     selector?: Function;
@@ -436,25 +422,21 @@ export interface PivotGridDataSourceField {
     showTotals?: boolean;
     /**
      * @docid PivotGridDataSourceOptions.fields.showValues
-     * @default undefined
      * @public
      */
     showValues?: boolean;
     /**
      * @docid PivotGridDataSourceOptions.fields.sortBy
-     * @default undefined
      * @public
      */
     sortBy?: PivotGridSortBy;
     /**
      * @docid PivotGridDataSourceOptions.fields.sortBySummaryField
-     * @default undefined
      * @public
      */
     sortBySummaryField?: string;
     /**
      * @docid PivotGridDataSourceOptions.fields.sortBySummaryPath
-     * @default undefined
      * @public
      */
     sortBySummaryPath?: Array<number | string>;
@@ -466,13 +448,11 @@ export interface PivotGridDataSourceField {
     sortOrder?: SortOrder;
     /**
      * @docid PivotGridDataSourceOptions.fields.sortingMethod
-     * @default undefined
      * @public
      */
     sortingMethod?: ((a: { value?: string | number; children?: Array<any> }, b: { value?: string | number; children?: Array<any> }) => number);
     /**
      * @docid PivotGridDataSourceOptions.fields.summaryDisplayMode
-     * @default undefined
      * @public
      */
     summaryDisplayMode?: PivotGridSummaryDisplayMode;
@@ -490,13 +470,11 @@ export interface PivotGridDataSourceField {
     visible?: boolean;
     /**
      * @docid PivotGridDataSourceOptions.fields.width
-     * @default undefined
      * @public
      */
     width?: number;
     /**
      * @docid PivotGridDataSourceOptions.fields.wordWrapEnabled
-     * @default undefined
      * @public
      */
     wordWrapEnabled?: boolean;
diff --git a/packages/devextreme/js/ui/pivot_grid_field_chooser.d.ts b/packages/devextreme/js/ui/pivot_grid_field_chooser.d.ts
index b102bf191fb3..8dec03205fdf 100644
--- a/packages/devextreme/js/ui/pivot_grid_field_chooser.d.ts
+++ b/packages/devextreme/js/ui/pivot_grid_field_chooser.d.ts
@@ -193,12 +193,12 @@ export interface dxPivotGridFieldChooserOptions extends WidgetOptions<dxPivotGri
     /**
      * @docid
      * @type_function_param1 e:{ui/pivot_grid_field_chooser:ContextMenuPreparingEvent}
-     * @default null
+     * @default undefined
 
      * @action
      * @public
      */
-    onContextMenuPreparing?: ((e: ContextMenuPreparingEvent) => void);
+    onContextMenuPreparing?: ((e: ContextMenuPreparingEvent) => void) | undefined;
     /**
      * @docid
      * @default 500
@@ -207,10 +207,10 @@ export interface dxPivotGridFieldChooserOptions extends WidgetOptions<dxPivotGri
     searchTimeout?: number;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @public
      */
-    state?: any;
+    state?: any | undefined;
     /**
      * @docid
      * @public
diff --git a/packages/devextreme/js/ui/scheduler.d.ts b/packages/devextreme/js/ui/scheduler.d.ts
index e7bcc32063fd..e1ed7c0125d4 100644
--- a/packages/devextreme/js/ui/scheduler.d.ts
+++ b/packages/devextreme/js/ui/scheduler.d.ts
@@ -593,11 +593,11 @@ export interface dxSchedulerOptions extends WidgetOptions<dxScheduler> {
     customizeDateNavigatorText?: ((info: DateNavigatorTextInfo) => string) | undefined;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type_function_param1 itemData:object
      * @public
      */
-    dataCellTemplate?: template | ((itemData: any, itemIndex: number, itemElement: DxElement) => string | UserDefinedElement);
+    dataCellTemplate?: template | ((itemData: any, itemIndex: number, itemElement: DxElement) => string | UserDefinedElement) | undefined;
     /**
      * @docid
      * @default null
@@ -607,11 +607,11 @@ export interface dxSchedulerOptions extends WidgetOptions<dxScheduler> {
     dataSource?: DataSourceLike<Appointment> | null;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type_function_param1 itemData:object
      * @public
      */
-    dateCellTemplate?: template | ((itemData: any, itemIndex: number, itemElement: DxElement) => string | UserDefinedElement);
+    dateCellTemplate?: template | ((itemData: any, itemIndex: number, itemElement: DxElement) => string | UserDefinedElement) | undefined;
     /**
      * @docid
      * @default undefined
@@ -754,113 +754,113 @@ export interface dxSchedulerOptions extends WidgetOptions<dxScheduler> {
     noDataText?: string;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type_function_param1 e:{ui/scheduler:AppointmentAddedEvent}
      * @action
      * @public
      */
-    onAppointmentAdded?: ((e: AppointmentAddedEvent) => void);
+    onAppointmentAdded?: ((e: AppointmentAddedEvent) => void) | undefined;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type_function_param1 e:{ui/scheduler:AppointmentAddingEvent}
      * @action
      * @public
      */
-    onAppointmentAdding?: ((e: AppointmentAddingEvent) => void);
+    onAppointmentAdding?: ((e: AppointmentAddingEvent) => void) | undefined;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type function
      * @type_function_param1 e:{ui/scheduler:AppointmentClickEvent}
      * @action
      * @public
      */
-    onAppointmentClick?: ((e: AppointmentClickEvent) => void) | string;
+    onAppointmentClick?: ((e: AppointmentClickEvent) => void) | string | undefined;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type function
      * @type_function_param1 e:{ui/scheduler:AppointmentContextMenuEvent}
      * @action
      * @public
      */
-    onAppointmentContextMenu?: ((e: AppointmentContextMenuEvent) => void) | string;
+    onAppointmentContextMenu?: ((e: AppointmentContextMenuEvent) => void) | string | undefined;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type function
      * @type_function_param1 e:{ui/scheduler:AppointmentDblClickEvent}
      * @action
      * @public
      */
-    onAppointmentDblClick?: ((e: AppointmentDblClickEvent) => void) | string;
+    onAppointmentDblClick?: ((e: AppointmentDblClickEvent) => void) | string | undefined;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type_function_param1 e:{ui/scheduler:AppointmentDeletedEvent}
      * @action
      * @public
      */
-    onAppointmentDeleted?: ((e: AppointmentDeletedEvent) => void);
+    onAppointmentDeleted?: ((e: AppointmentDeletedEvent) => void) | undefined;
 
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type_function_param1 e:{ui/scheduler:AppointmentDeletingEvent}
      * @action
      * @public
      */
-    onAppointmentDeleting?: ((e: AppointmentDeletingEvent) => void);
+    onAppointmentDeleting?: ((e: AppointmentDeletingEvent) => void) | undefined;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type_function_param1 e:{ui/scheduler:AppointmentTooltipShowingEvent}
      * @action
      * @public
      */
-    onAppointmentTooltipShowing?: ((e: AppointmentTooltipShowingEvent) => void);
+    onAppointmentTooltipShowing?: ((e: AppointmentTooltipShowingEvent) => void) | undefined;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type_function_param1 e:{ui/scheduler:AppointmentFormOpeningEvent}
      * @action
      * @public
      */
-    onAppointmentFormOpening?: ((e: AppointmentFormOpeningEvent) => void);
+    onAppointmentFormOpening?: ((e: AppointmentFormOpeningEvent) => void) | undefined;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type_function_param1 e:{ui/scheduler:AppointmentRenderedEvent}
      * @action
      * @public
      */
-    onAppointmentRendered?: ((e: AppointmentRenderedEvent) => void);
+    onAppointmentRendered?: ((e: AppointmentRenderedEvent) => void) | undefined;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type_function_param1 e:{ui/scheduler:AppointmentUpdatedEvent}
      * @action
      * @public
      */
-    onAppointmentUpdated?: ((e: AppointmentUpdatedEvent) => void);
+    onAppointmentUpdated?: ((e: AppointmentUpdatedEvent) => void) | undefined;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type_function_param1 e:{ui/scheduler:AppointmentUpdatingEvent}
      * @action
      * @public
      */
-    onAppointmentUpdating?: ((e: AppointmentUpdatingEvent) => void);
+    onAppointmentUpdating?: ((e: AppointmentUpdatingEvent) => void) | undefined;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type function
      * @type_function_param1 e:{ui/scheduler:CellClickEvent}
      * @action
      * @public
      */
-    onCellClick?: ((e: CellClickEvent) => void) | string;
+    onCellClick?: ((e: CellClickEvent) => void) | string | undefined;
     /**
      * @docid
      * @default undefined
@@ -871,13 +871,13 @@ export interface dxSchedulerOptions extends WidgetOptions<dxScheduler> {
     onSelectionEnd?: ((e: SelectionEndEvent) => void) | undefined;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type function
      * @type_function_param1 e:{ui/scheduler:CellContextMenuEvent}
      * @action
      * @public
      */
-    onCellContextMenu?: ((e: CellContextMenuEvent) => void) | string;
+    onCellContextMenu?: ((e: CellContextMenuEvent) => void) | string | undefined;
     /**
      * @docid
      * @default "dialog"
@@ -904,11 +904,11 @@ export interface dxSchedulerOptions extends WidgetOptions<dxScheduler> {
     remoteFiltering?: boolean;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type_function_param1 itemData:object
      * @public
      */
-    resourceCellTemplate?: template | ((itemData: any, itemIndex: number, itemElement: DxElement) => string | UserDefinedElement);
+    resourceCellTemplate?: template | ((itemData: any, itemIndex: number, itemElement: DxElement) => string | UserDefinedElement) | undefined;
     /**
      * @docid
      * @default []
@@ -1019,11 +1019,11 @@ export interface dxSchedulerOptions extends WidgetOptions<dxScheduler> {
     textExpr?: string;
     /**
      * @docid
-     * @default null
+     * @default undefined
      * @type_function_param1 itemData:object
      * @public
      */
-    timeCellTemplate?: template | ((itemData: any, itemIndex: number, itemElement: DxElement) => string | UserDefinedElement);
+    timeCellTemplate?: template | ((itemData: any, itemIndex: number, itemElement: DxElement) => string | UserDefinedElement) | undefined;
     /**
      * @docid
      * @default ""
@@ -1094,13 +1094,11 @@ export interface dxSchedulerOptions extends WidgetOptions<dxScheduler> {
       cellDuration?: number;
       /**
        * @docid
-       * @default null
        * @type_function_param1 itemData:object
        */
       dataCellTemplate?: template | ((itemData: any, itemIndex: number, itemElement: DxElement) => string | UserDefinedElement);
       /**
        * @docid
-       * @default null
        * @type_function_param1 itemData:object
        */
       dateCellTemplate?: template | ((itemData: any, itemIndex: number, itemElement: DxElement) => string | UserDefinedElement);
@@ -1150,7 +1148,6 @@ export interface dxSchedulerOptions extends WidgetOptions<dxScheduler> {
       name?: string | undefined;
       /**
        * @docid
-       * @default null
        * @type_function_param1 itemData:object
        */
       resourceCellTemplate?: template | ((itemData: any, itemIndex: number, itemElement: DxElement) => string | UserDefinedElement);
@@ -1166,7 +1163,6 @@ export interface dxSchedulerOptions extends WidgetOptions<dxScheduler> {
       startDayHour?: number;
       /**
        * @docid
-       * @default null
        * @type_function_param1 itemData:object
        */
       timeCellTemplate?: template | ((itemData: any, itemIndex: number, itemElement: DxElement) => string | UserDefinedElement);
diff --git a/packages/devextreme/testing/tests/DevExpress.ui.widgets.pivotGrid/fieldChooser.tests.js b/packages/devextreme/testing/tests/DevExpress.ui.widgets.pivotGrid/fieldChooser.tests.js
index f3b54ed0e922..d400f8525f96 100644
--- a/packages/devextreme/testing/tests/DevExpress.ui.widgets.pivotGrid/fieldChooser.tests.js
+++ b/packages/devextreme/testing/tests/DevExpress.ui.widgets.pivotGrid/fieldChooser.tests.js
@@ -2473,7 +2473,7 @@ QUnit.module('applyChangesMode: onDemand', {
 
         // assert
         assert.strictEqual(isCanceled, false, 'cancelChanges return false');
-        assert.strictEqual(this.fieldChooser.option('state'), null, 'state is empty');
+        assert.strictEqual(this.fieldChooser.option('state'), undefined, 'state is empty');
     });
 
     QUnit.test('cancel changes on field chooser repaint', function(assert) {
diff --git a/packages/devextreme/ts/dx.all.d.ts b/packages/devextreme/ts/dx.all.d.ts
index d915f281adee..c5c87abf46c9 100644
--- a/packages/devextreme/ts/dx.all.d.ts
+++ b/packages/devextreme/ts/dx.all.d.ts
@@ -8082,7 +8082,7 @@ declare module DevExpress.data {
     /**
      * [descr:PivotGridDataSourceOptions.fields]
      */
-    fields?: Array<DevExpress.data.PivotGridDataSource.Field>;
+    fields?: Array<DevExpress.data.PivotGridDataSource.Field> | undefined;
     /**
      * [descr:PivotGridDataSourceOptions.filter]
      */
@@ -24773,9 +24773,11 @@ declare module DevExpress.ui {
     /**
      * [descr:dxPivotGridFieldChooserOptions.onContextMenuPreparing]
      */
-    onContextMenuPreparing?: (
-      e: DevExpress.ui.dxPivotGridFieldChooser.ContextMenuPreparingEvent
-    ) => void;
+    onContextMenuPreparing?:
+      | ((
+          e: DevExpress.ui.dxPivotGridFieldChooser.ContextMenuPreparingEvent
+        ) => void)
+      | undefined;
     /**
      * [descr:dxPivotGridFieldChooserOptions.searchTimeout]
      */
@@ -24783,7 +24785,7 @@ declare module DevExpress.ui {
     /**
      * [descr:dxPivotGridFieldChooserOptions.state]
      */
-    state?: any;
+    state?: any | undefined;
     /**
      * [descr:dxPivotGridFieldChooserOptions.texts]
      */
@@ -25069,21 +25071,27 @@ declare module DevExpress.ui {
     /**
      * [descr:dxPivotGridOptions.onCellClick]
      */
-    onCellClick?: (e: DevExpress.ui.dxPivotGrid.CellClickEvent) => void;
+    onCellClick?:
+      | ((e: DevExpress.ui.dxPivotGrid.CellClickEvent) => void)
+      | undefined;
     /**
      * [descr:dxPivotGridOptions.onCellPrepared]
      */
-    onCellPrepared?: (e: DevExpress.ui.dxPivotGrid.CellPreparedEvent) => void;
+    onCellPrepared?:
+      | ((e: DevExpress.ui.dxPivotGrid.CellPreparedEvent) => void)
+      | undefined;
     /**
      * [descr:dxPivotGridOptions.onContextMenuPreparing]
      */
-    onContextMenuPreparing?: (
-      e: DevExpress.ui.dxPivotGrid.ContextMenuPreparingEvent
-    ) => void;
+    onContextMenuPreparing?:
+      | ((e: DevExpress.ui.dxPivotGrid.ContextMenuPreparingEvent) => void)
+      | undefined;
     /**
      * [descr:dxPivotGridOptions.onExporting]
      */
-    onExporting?: (e: DevExpress.ui.dxPivotGrid.ExportingEvent) => void;
+    onExporting?:
+      | ((e: DevExpress.ui.dxPivotGrid.ExportingEvent) => void)
+      | undefined;
     /**
      * [descr:dxPivotGridOptions.rowHeaderLayout]
      */
@@ -25148,7 +25156,7 @@ declare module DevExpress.ui {
       /**
        * [descr:dxPivotGridOptions.stateStoring.storageKey]
        */
-      storageKey?: string;
+      storageKey?: string | undefined;
       /**
        * [descr:dxPivotGridOptions.stateStoring.type]
        */
@@ -26903,7 +26911,8 @@ declare module DevExpress.ui {
           itemData: any,
           itemIndex: number,
           itemElement: DevExpress.core.DxElement
-        ) => string | DevExpress.core.UserDefinedElement);
+        ) => string | DevExpress.core.UserDefinedElement)
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.dataSource]
      */
@@ -26917,7 +26926,8 @@ declare module DevExpress.ui {
           itemData: any,
           itemIndex: number,
           itemElement: DevExpress.core.DxElement
-        ) => string | DevExpress.core.UserDefinedElement);
+        ) => string | DevExpress.core.UserDefinedElement)
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.dateSerializationFormat]
      */
@@ -27022,82 +27032,86 @@ declare module DevExpress.ui {
     /**
      * [descr:dxSchedulerOptions.onAppointmentAdded]
      */
-    onAppointmentAdded?: (
-      e: DevExpress.ui.dxScheduler.AppointmentAddedEvent
-    ) => void;
+    onAppointmentAdded?:
+      | ((e: DevExpress.ui.dxScheduler.AppointmentAddedEvent) => void)
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.onAppointmentAdding]
      */
-    onAppointmentAdding?: (
-      e: DevExpress.ui.dxScheduler.AppointmentAddingEvent
-    ) => void;
+    onAppointmentAdding?:
+      | ((e: DevExpress.ui.dxScheduler.AppointmentAddingEvent) => void)
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.onAppointmentClick]
      */
     onAppointmentClick?:
       | ((e: DevExpress.ui.dxScheduler.AppointmentClickEvent) => void)
-      | string;
+      | string
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.onAppointmentContextMenu]
      */
     onAppointmentContextMenu?:
       | ((e: DevExpress.ui.dxScheduler.AppointmentContextMenuEvent) => void)
-      | string;
+      | string
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.onAppointmentDblClick]
      */
     onAppointmentDblClick?:
       | ((e: DevExpress.ui.dxScheduler.AppointmentDblClickEvent) => void)
-      | string;
+      | string
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.onAppointmentDeleted]
      */
-    onAppointmentDeleted?: (
-      e: DevExpress.ui.dxScheduler.AppointmentDeletedEvent
-    ) => void;
+    onAppointmentDeleted?:
+      | ((e: DevExpress.ui.dxScheduler.AppointmentDeletedEvent) => void)
+      | undefined;
 
     /**
      * [descr:dxSchedulerOptions.onAppointmentDeleting]
      */
-    onAppointmentDeleting?: (
-      e: DevExpress.ui.dxScheduler.AppointmentDeletingEvent
-    ) => void;
+    onAppointmentDeleting?:
+      | ((e: DevExpress.ui.dxScheduler.AppointmentDeletingEvent) => void)
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.onAppointmentTooltipShowing]
      */
-    onAppointmentTooltipShowing?: (
-      e: DevExpress.ui.dxScheduler.AppointmentTooltipShowingEvent
-    ) => void;
+    onAppointmentTooltipShowing?:
+      | ((e: DevExpress.ui.dxScheduler.AppointmentTooltipShowingEvent) => void)
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.onAppointmentFormOpening]
      */
-    onAppointmentFormOpening?: (
-      e: DevExpress.ui.dxScheduler.AppointmentFormOpeningEvent
-    ) => void;
+    onAppointmentFormOpening?:
+      | ((e: DevExpress.ui.dxScheduler.AppointmentFormOpeningEvent) => void)
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.onAppointmentRendered]
      */
-    onAppointmentRendered?: (
-      e: DevExpress.ui.dxScheduler.AppointmentRenderedEvent
-    ) => void;
+    onAppointmentRendered?:
+      | ((e: DevExpress.ui.dxScheduler.AppointmentRenderedEvent) => void)
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.onAppointmentUpdated]
      */
-    onAppointmentUpdated?: (
-      e: DevExpress.ui.dxScheduler.AppointmentUpdatedEvent
-    ) => void;
+    onAppointmentUpdated?:
+      | ((e: DevExpress.ui.dxScheduler.AppointmentUpdatedEvent) => void)
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.onAppointmentUpdating]
      */
-    onAppointmentUpdating?: (
-      e: DevExpress.ui.dxScheduler.AppointmentUpdatingEvent
-    ) => void;
+    onAppointmentUpdating?:
+      | ((e: DevExpress.ui.dxScheduler.AppointmentUpdatingEvent) => void)
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.onCellClick]
      */
     onCellClick?:
       | ((e: DevExpress.ui.dxScheduler.CellClickEvent) => void)
-      | string;
+      | string
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.onSelectionEnd]
      */
@@ -27109,7 +27123,8 @@ declare module DevExpress.ui {
      */
     onCellContextMenu?:
       | ((e: DevExpress.ui.dxScheduler.CellContextMenuEvent) => void)
-      | string;
+      | string
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.recurrenceEditMode]
      */
@@ -27135,7 +27150,8 @@ declare module DevExpress.ui {
           itemData: any,
           itemIndex: number,
           itemElement: DevExpress.core.DxElement
-        ) => string | DevExpress.core.UserDefinedElement);
+        ) => string | DevExpress.core.UserDefinedElement)
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.resources]
      */
@@ -27222,7 +27238,8 @@ declare module DevExpress.ui {
           itemData: any,
           itemIndex: number,
           itemElement: DevExpress.core.DxElement
-        ) => string | DevExpress.core.UserDefinedElement);
+        ) => string | DevExpress.core.UserDefinedElement)
+      | undefined;
     /**
      * [descr:dxSchedulerOptions.timeZone]
      */