add NotebookEditorCellEdit#replaceOutputs, https://github.com/microsoft/vscode/issues/105283

src/vs/vscode.proposed.d.ts

@@ -1357,6 +1357,8 @@ declare module 'vscode' {
 
 		replaceCells(from: number, to: number, cells: NotebookCellData[]): void;
 
+		replaceOutputs(index: number, outputs: CellOutput[]): void;
+
 		/** @deprecated */
 		insert(index: number, content: string | string[], language: string, type: CellKind, outputs: CellOutput[], metadata: NotebookCellMetadata | undefined): void;
 		/** @deprecated */

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

@@ -560,7 +560,7 @@ export class MainThreadNotebooks extends Disposable implements MainThreadNoteboo
 
 		if (textModel) {
 			this._notebookService.transformSpliceOutputs(textModel, splices);
-			textModel.$spliceNotebookCellOutputs(cellHandle, splices);
+			textModel.spliceNotebookCellOutputs(cellHandle, splices);
 		}
 	}
 

src/vs/workbench/api/common/extHostNotebook.ts

@@ -511,6 +511,15 @@ export class NotebookEditorCellEditBuilder implements vscode.NotebookEditorCellE
 		}
 	}
 
+	replaceOutputs(index: number, outputs: vscode.CellOutput[]): void {
+		this._throwIfFinalized();
+		this._collectedEdits.push({
+			editType: CellEditType.Output,
+			index,
+			outputs: outputs.map(output => addIdToOutput(output))
+		});
+	}
+
 	replaceCells(from: number, to: number, cells: vscode.NotebookCellData[]): void {
 		this._throwIfFinalized();
 

src/vs/workbench/contrib/notebook/browser/notebookServiceImpl.ts

@@ -733,6 +733,16 @@ export class NotebookService extends Disposable implements INotebookService, ICu
 						}
 					});
 				});
+			} else if (edit.editType === CellEditType.Output) {
+				edit.outputs.map((output) => {
+					if (output.outputKind === CellOutputKind.Rich) {
+						const ret = this._transformMimeTypes(output, output.outputId, textModel.metadata.displayOrder as string[] || []);
+						const orderedMimeTypes = ret.orderedMimeTypes!;
+						const pickedMimeTypeIndex = ret.pickedMimeTypeIndex!;
+						output.pickedMimeTypeIndex = pickedMimeTypeIndex;
+						output.orderedMimeTypes = orderedMimeTypes;
+					}
+				});
 			}
 		});
 	}

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

@@ -8,7 +8,7 @@ import { Emitter, Event } from 'vs/base/common/event';
 import { Disposable, IDisposable } from 'vs/base/common/lifecycle';
 import { URI } from 'vs/base/common/uri';
 import { NotebookCellTextModel } from 'vs/workbench/contrib/notebook/common/model/notebookCellTextModel';
-import { INotebookTextModel, NotebookCellOutputsSplice, NotebookCellTextModelSplice, NotebookDocumentMetadata, NotebookCellMetadata, ICellEditOperation, CellEditType, CellUri, ICellInsertEdit, NotebookCellsChangedEvent, CellKind, IProcessedOutput, notebookDocumentMetadataDefaults, diff, ICellDeleteEdit, NotebookCellsChangeType, ICellDto2, IMainCellDto } from 'vs/workbench/contrib/notebook/common/notebookCommon';
+import { INotebookTextModel, NotebookCellOutputsSplice, NotebookCellTextModelSplice, NotebookDocumentMetadata, NotebookCellMetadata, ICellEditOperation, CellEditType, CellUri, ICellInsertEdit, NotebookCellsChangedEvent, CellKind, IProcessedOutput, notebookDocumentMetadataDefaults, diff, ICellDeleteEdit, NotebookCellsChangeType, ICellDto2, IMainCellDto, ICellOutputEdit } from 'vs/workbench/contrib/notebook/common/notebookCommon';
 import { ITextSnapshot } from 'vs/editor/common/model';
 import { IUndoRedoService, UndoRedoElementType, IUndoRedoElement, IResourceUndoRedoElement } from 'vs/platform/undoRedo/common/undoRedo';
 import { InsertCellEdit, DeleteCellEdit, MoveCellEdit, SpliceCellsEdit } from 'vs/workbench/contrib/notebook/common/model/cellEdit';
@@ -279,6 +279,11 @@ export class NotebookTextModel extends Disposable implements INotebookTextModel
 				case CellEditType.Delete:
 					this.removeCell(operations[i].index, operations[i].end - operations[i].start, false);
 					break;
+				case CellEditType.Output:
+					//TODO@joh,@rebornix no event, no undo stop (?)
+					const cell = this.cells[operations[i].index];
+					this.spliceNotebookCellOutputs(cell.handle, [[0, cell.outputs.length, (<ICellOutputEdit>operations[i]).outputs]]);
+					break;
 			}
 		}
 
@@ -493,7 +498,7 @@ export class NotebookTextModel extends Disposable implements INotebookTextModel
 	}
 
 	// TODO@rebornix should this trigger content change event?
-	$spliceNotebookCellOutputs(cellHandle: number, splices: NotebookCellOutputsSplice[]): void {
+	spliceNotebookCellOutputs(cellHandle: number, splices: NotebookCellOutputsSplice[]): void {
 		const cell = this._mapping.get(cellHandle);
 		cell?.spliceNotebookCellOutputs(splices);
 	}

src/vs/workbench/contrib/notebook/common/notebookCommon.ts

@@ -398,9 +398,11 @@ export interface NotebookCellsChangeMetadataEvent {
 }
 
 export type NotebookCellsChangedEvent = NotebookCellsInitializeEvent | NotebookCellsModelChangedEvent | NotebookCellsModelMoveEvent | NotebookCellClearOutputEvent | NotebookCellsClearOutputEvent | NotebookCellsChangeLanguageEvent | NotebookCellsChangeMetadataEvent;
-export enum CellEditType {
+
+export const enum CellEditType {
 	Insert = 1,
-	Delete = 2
+	Delete = 2,
+	Output = 3,
 }
 
 export interface ICellDto2 {
@@ -423,7 +425,13 @@ export interface ICellDeleteEdit {
 	count: number;
 }
 
-export type ICellEditOperation = ICellInsertEdit | ICellDeleteEdit;
+export interface ICellOutputEdit {
+	editType: CellEditType.Output;
+	index: number,
+	outputs: IProcessedOutput[]
+}
+
+export type ICellEditOperation = ICellInsertEdit | ICellDeleteEdit | ICellOutputEdit;
 
 export interface INotebookEditData {
 	documentVersionId: number;