reduce usage of arrays#flatten util, use native flat instead

src/vs/editor/contrib/suggest/browser/suggestWidgetRenderer.ts

@@ -7,7 +7,6 @@ import { isSafari } from 'vs/base/browser/browser';
 import { $, append, hide, show } from 'vs/base/browser/dom';
 import { IconLabel, IIconLabelValueOptions } from 'vs/base/browser/ui/iconLabel/iconLabel';
 import { IListRenderer } from 'vs/base/browser/ui/list/list';
-import { flatten } from 'vs/base/common/arrays';
 import { Codicon, CSSIcon } from 'vs/base/common/codicons';
 import { Emitter, Event } from 'vs/base/common/event';
 import { createMatches } from 'vs/base/common/filters';
@@ -190,10 +189,10 @@ export class ItemRenderer implements IListRenderer<CompletionItem, ISuggestionTe
 			// special logic for 'folder' completion items
 			data.icon.className = 'icon hide';
 			data.iconContainer.className = 'icon hide';
-			labelOptions.extraClasses = flatten([
+			labelOptions.extraClasses = [
 				getIconClasses(this._modelService, this._languageService, URI.from({ scheme: 'fake', path: element.textLabel }), FileKind.FOLDER),
 				getIconClasses(this._modelService, this._languageService, URI.from({ scheme: 'fake', path: completion.detail }), FileKind.FOLDER)
-			]);
+			].flat();
 		} else {
 			// normal icon
 			data.icon.className = 'icon hide';

src/vs/workbench/api/browser/mainThreadNotebookKernels.ts

@@ -3,7 +3,7 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { flatten, isNonEmptyArray } from 'vs/base/common/arrays';
+import { isNonEmptyArray } from 'vs/base/common/arrays';
 import { onUnexpectedError } from 'vs/base/common/errors';
 import { Emitter, Event } from 'vs/base/common/event';
 import { combinedDisposable, DisposableStore, IDisposable, toDisposable } from 'vs/base/common/lifecycle';
@@ -43,7 +43,7 @@ abstract class MainThreadKernel implements INotebookKernel {
 	}
 
 	public get preloadProvides() {
-		return flatten(this.preloads.map(p => p.provides));
+		return this.preloads.map(p => p.provides).flat();
 	}
 
 	constructor(data: INotebookKernelDto2, private _languageService: ILanguageService) {

src/vs/workbench/contrib/notebook/browser/contrib/cellStatusBar/contributedStatusBarItemController.ts

@@ -3,7 +3,6 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { flatten } from 'vs/base/common/arrays';
 import { disposableTimeout, Throttler } from 'vs/base/common/async';
 import { CancellationTokenSource } from 'vs/base/common/cancellation';
 import { Disposable, toDisposable } from 'vs/base/common/lifecycle';
@@ -119,7 +118,7 @@ class CellStatusBarHelper extends Disposable {
 			return;
 		}
 
-		const items = flatten(itemLists.map(itemList => itemList.items));
+		const items = itemLists.map(itemList => itemList.items).flat();
 		const newIds = this._notebookViewModel.deltaCellStatusBarItems(this._currentItemIds, [{ handle: this._cell.handle, items }]);
 
 		this._currentItemLists.forEach(itemList => itemList.dispose && itemList.dispose());

src/vs/workbench/contrib/notebook/browser/contrib/format/formatting.ts

@@ -23,7 +23,6 @@ import { EditorContextKeys } from 'vs/editor/common/editorContextKeys';
 import { registerEditorAction, EditorAction } from 'vs/editor/browser/editorExtensions';
 import { ICodeEditor } from 'vs/editor/browser/editorBrowser';
 import { Progress } from 'vs/platform/progress/common/progress';
-import { flatten } from 'vs/base/common/arrays';
 import { ILanguageFeaturesService } from 'vs/editor/common/services/languageFeatures';
 
 // format notebook
@@ -91,7 +90,7 @@ registerAction2(class extends Action2 {
 				return [];
 			}));
 
-			await bulkEditService.apply(/* edit */flatten(allCellEdits), { label: localize('label', "Format Notebook"), code: 'undoredo.formatNotebook', });
+			await bulkEditService.apply(/* edit */allCellEdits.flat(), { label: localize('label', "Format Notebook"), code: 'undoredo.formatNotebook', });
 
 		} finally {
 			disposable.dispose();

src/vs/workbench/contrib/notebook/common/model/notebookTextModel.ts

@@ -3,7 +3,6 @@
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
 
-import { flatten } from 'vs/base/common/arrays';
 import { Emitter, Event, PauseableEmitter } from 'vs/base/common/event';
 import { Disposable, dispose, IDisposable } from 'vs/base/common/lifecycle';
 import { URI } from 'vs/base/common/uri';
@@ -502,7 +501,7 @@ export class NotebookTextModel extends Disposable implements INotebookTextModel
 				return [...otherEdits.reverse(), ...replaceEdits];
 			});
 
-		const flattenEdits = flatten(edits);
+		const flattenEdits = edits.flat();
 
 		for (const { edit, cellIndex } of flattenEdits) {
 			switch (edit.editType) {