GridCore - DataController - Add types (processItems pipeline)- #34693 by Tucchhaa · Pull Request #34719 · DevExpress/DevExtreme

Tucchhaa · 2026-08-10T12:56:54Z

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Copilot

Pull request overview

This PR strengthens TypeScript typings across the GridCore DataController “processItems → generate/process data item” pipeline, and updates several grid mixins to use the new typed contracts.

Changes:

Introduces RowGenerationOptions, GeneratedDataItem, and ProcessedDataItem types and updates DataController methods to use them.
Updates GridCore features (virtual scrolling, selection, master-detail, adaptivity, editing, filter sync) to use the typed pipeline methods instead of apply(this, arguments as any).
Adds/adjusts return types for Deferred-based APIs (_applyFilter, DataSource.store).

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
packages/devextreme/js/__internal/grids/tree_list/data_controller/m_data_controller.ts	Adds a TS suppression on TreeList’s `_generateDataItem` override (needs proper signature typing).
packages/devextreme/js/__internal/grids/grid_core/virtual_scrolling/m_virtual_scrolling.ts	Types `_processItems`/`_afterProcessItems` and `_applyFilter` for virtual scrolling pipeline.
packages/devextreme/js/__internal/grids/grid_core/selection/m_selection.ts	Types `_processDataItem` to operate on `GeneratedDataItem`/`ProcessedDataItem`.
packages/devextreme/js/__internal/grids/grid_core/master_detail/m_master_detail.ts	Types master-detail `_processItems`/`_processDataItem` and inserts detail rows.
packages/devextreme/js/__internal/grids/grid_core/filter/m_filter_sync.ts	Types `_applyFilter` to Deferred-based return and removes `arguments`-based calls.
packages/devextreme/js/__internal/grids/grid_core/editing/types.ts	Replaces `Item` with `ProcessedDataItem` in editing-related types.
packages/devextreme/js/__internal/grids/grid_core/editing/m_editing.ts	Types editing controller hooks (`processItems`, `processDataItem`) and data-controller overrides.
packages/devextreme/js/__internal/grids/grid_core/data_controller/types.ts	Adds new pipeline types (`RowGenerationOptions`, `GeneratedDataItem`, `ProcessedDataItem`).
packages/devextreme/js/__internal/grids/grid_core/data_controller/data_controller.ts	Refactors core pipeline methods to return typed processed items and updates Deferred return types.
packages/devextreme/js/__internal/grids/grid_core/ai_column/utils.ts	Updates helper signature to accept `ProcessedDataItem[]`.
packages/devextreme/js/__internal/grids/grid_core/ai_column/utils.test.ts	Updates test typing to match `ProcessedDataItem`.
packages/devextreme/js/__internal/grids/grid_core/adaptivity/m_adaptivity.ts	Types `_processItems` and preserves `values` when inserting adaptive detail rows.
packages/devextreme/js/__internal/data/data_source/m_data_source.ts	Types `store()` return and aligns Deferred usage in load flow.

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Copilot

Pull request overview

Copilot reviewed 13 out of 13 changed files in this pull request and generated no new comments.

Suppressed comments (2)

packages/devextreme/js/__internal/grids/tree_list/data_controller/m_data_controller.ts:26

The node parameter is marked optional, but the implementation dereferences it (node.key, node.data) without null checks. Making it optional weakens type safety and suggests callers may pass undefined, which would crash at runtime.

  protected _generateDataItem(node?: any, options?: any): any {

packages/devextreme/js/__internal/grids/grid_core/virtual_scrolling/m_virtual_scrolling.ts:769

newRows is typed as any[], which reintroduces any into an otherwise typed ProcessedDataItem pipeline and makes loadIndex mutations unchecked. It can be typed precisely as ProcessedDataItem[].

      let newRows: any = [];

Copilot

Pull request overview

Copilot reviewed 13 out of 13 changed files in this pull request and generated no new comments.

Suppressed comments (2)

packages/devextreme/js/__internal/grids/grid_core/data_controller/data_controller.ts:713

Avoid suppressing the type error here: changeType: 'append' is a real runtime value (see virtual_data_loader fireChanged with changeType 'append'), so it should be represented in the method’s parameter type instead of using @ts-expect-error. This keeps the typing accurate and removes the need for the suppression.

  protected getDataIndex(change: DataChange | { changeType: 'loadingAll' }): number {
    const visibleItems = this._items;
    // @ts-expect-error changeType can be 'append' only when virtual scrolling with scrolling.legacyMode are enabled
    const lastVisibleItem = change.changeType === 'append' && visibleItems.length > 0 ? visibleItems[visibleItems.length - 1] : null;

packages/devextreme/js/__internal/grids/tree_list/data_controller/m_data_controller.ts:26

This override is part of the DataController item-processing pipeline, but the new signature still uses optional any parameters and returns any, which undermines the purpose of adding pipeline types. It’s also misleading to make node optional since the implementation immediately dereferences it. Consider typing it to the shared ItemProcessingOptions/GeneratedItem types (even if node itself remains any).

  protected _generateDataItem(node?: any, options?: any): any {

anna-shakhova · 2026-08-10T14:20:46Z

+  protected getDataIndex(change: DataChange | { changeType: 'loadingAll' }): number {
    const visibleItems = this._items;
+    // @ts-expect-error changeType can be 'append' only when virtual scrolling with scrolling.legacyMode are enabled
    const lastVisibleItem = change.changeType === 'append' && visibleItems.length > 0 ? visibleItems[visibleItems.length - 1] : null;


looks like lastVisibleItem may be not null only in virtual scrolling with legacy mode. Shouldn't it then be moved there? and in base it should always return 0?

nitpick:

Suggested change

const lastVisibleItem = change.changeType === 'append' && visibleItems.length > 0 ? visibleItems[visibleItems.length - 1] : null;

const lastVisibleItem = change.changeType === 'append' && visibleItems.length > 0 ? visibleItems.at(-1) : null;

anna-shakhova · 2026-08-10T14:50:13Z


-      for (let index = 0; index < columnCount; index++) {
+      for (let index = 0; index < columnCount; index += 1) {
        columnsController.columnOption(index, optionName, undefined);


each columnOption method call will trigger columnsChanged event
the whole clearColumnOption looks like candidate to be extracted as columnsController method, and here later we will be able to introduce some decision how to trigger event just once (I think it is ok just to highlight it inside columnsController and fix it later during columnsController refactoring )

each columnOption method call will trigger columnsChanged event

No, it won't because of updateLockCount in fireColumnsChanged and beginUpdate/endUpdate wrapping

Copilot

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated no new comments.

Suppressed comments (1)

packages/devextreme/js/__internal/grids/tree_list/data_controller/m_data_controller.ts:26

_generateDataItem is now typed with optional params and an any return type, which effectively disables the type-safety this PR is trying to introduce. Since this override always expects a node and returns a well-known object shape, it should have a concrete signature (at least avoiding any).

  protected _generateDataItem(node?: any, options?: any): any {

Copilot

Pull request overview

Copilot reviewed 16 out of 16 changed files in this pull request and generated no new comments.

Suppressed comments (1)

packages/devextreme/js/__internal/grids/tree_list/data_controller/m_data_controller.ts:26

node is marked optional, but the implementation dereferences it unconditionally (node.key, node.data, node.parent). Keeping it optional weakens type-safety and can mask real call-site issues. Make node a required parameter.

  protected _generateDataItem(node?: any, options?: any): any {

fix

4c8b3be

Tucchhaa self-assigned this Aug 10, 2026

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Eldar Iusupzhanov added 2 commits August 10, 2026 21:24

apply code style review comments

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move to virtual scrolling

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fix ts

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	const lastVisibleItem = change.changeType === 'append' && visibleItems.length > 0 ? visibleItems[visibleItems.length - 1] : null;
	const lastVisibleItem = change.changeType === 'append' && visibleItems.length > 0 ? visibleItems.at(-1) : null;

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Tucchhaa commented Aug 10, 2026

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