Add JSError renderer, experiment with NotebookCellOutputItem#error-factory function, https://github.com/microsoft/vscode/issues/120063

src/vs/vscode.proposed.d.ts

@@ -1271,9 +1271,17 @@ declare module 'vscode' {
 		// static textplain(value:string): NotebookCellOutputItem;
 		// static errortrace(value:any): NotebookCellOutputItem;
 
+		/**
+		 * Creates `application/x.notebook.error`
+		 *
+		 * @param err An error for which an output item is wanted
+		 */
+		static error(err: Error): NotebookCellOutputItem;
+
 		mime: string;
 
 		//todo@API string or Unit8Array?
+		// value: string | Uint8Array | unknown;
 		value: unknown;
 
 		metadata?: { [key: string]: any };

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

@@ -3087,6 +3087,13 @@ export class NotebookCellOutputItem {
 		return typeof (<vscode.NotebookCellOutputItem>obj).mime === 'string';
 	}
 
+	static error(err: Error): NotebookCellOutputItem {
+		return new NotebookCellOutputItem(
+			'application/x.notebook.error',
+			JSON.stringify({ name: err.name, message: err.message, stack: err.stack })
+		);
+	}
+
 	constructor(
 		public mime: string,
 		public value: unknown, // JSON'able

src/vs/workbench/contrib/notebook/browser/view/output/transforms/richTransform.ts

@@ -14,6 +14,7 @@ import { IEditorOptions } from 'vs/editor/common/config/editorOptions';
 import { IModelService } from 'vs/editor/common/services/modelService';
 import { IModeService } from 'vs/editor/common/services/modeService';
 import { IInstantiationService } from 'vs/platform/instantiation/common/instantiation';
+import { ILogService } from 'vs/platform/log/common/log';
 import { IOpenerService } from 'vs/platform/opener/common/opener';
 import { IThemeService } from 'vs/platform/theme/common/themeService';
 import { handleANSIOutput } from 'vs/workbench/contrib/debug/browser/debugANSIHandling';
@@ -277,6 +278,64 @@ class ErrorRendererContrib extends Disposable implements IOutputRendererContribu
 	}
 }
 
+class JSErrorRendererContrib implements IOutputRendererContribution {
+
+	constructor(
+		public notebookEditor: ICommonNotebookEditor,
+		@IThemeService private readonly _themeService: IThemeService,
+		@IInstantiationService private readonly _instantiationService: IInstantiationService,
+		@ILogService private readonly _logService: ILogService,
+	) { }
+
+	dispose(): void {
+		// nothing
+	}
+
+	getType() {
+		return RenderOutputType.Mainframe;
+	}
+
+	getMimetypes() {
+		return ['application/x.notebook.error'];
+	}
+
+	render(_output: ICellOutputViewModel, items: IOutputItemDto[], container: HTMLElement, _notebookUri: URI): IRenderOutput {
+		const linkDetector = this._instantiationService.createInstance(LinkDetector);
+
+		for (let item of items) {
+
+			if (typeof item.value !== 'string') {
+				this._logService.warn('INVALID output item (not a string)', item.value);
+				continue;
+			}
+
+			let err: Error;
+			try {
+				err = <Error>JSON.parse(item.value);
+			} catch (e) {
+				this._logService.warn('INVALID output item (failed to parse)', e);
+				continue;
+			}
+
+			const header = document.createElement('div');
+			const headerMessage = err.name && err.message ? `${err.name}: ${err.message}` : err.name || err.message;
+			if (headerMessage) {
+				header.innerText = headerMessage;
+				container.appendChild(header);
+			}
+			const stack = document.createElement('pre');
+			stack.classList.add('traceback');
+			if (err.stack) {
+				stack.appendChild(handleANSIOutput(err.stack, linkDetector, this._themeService, undefined));
+			}
+			container.appendChild(stack);
+			container.classList.add('error');
+		}
+
+		return { type: RenderOutputType.Mainframe };
+	}
+}
+
 class PlainTextRendererContrib extends Disposable implements IOutputRendererContribution {
 	getType() {
 		return RenderOutputType.Mainframe;
@@ -459,6 +518,7 @@ NotebookRegistry.registerOutputTransform('jpeg', JPEGRendererContrib);
 NotebookRegistry.registerOutputTransform('plain', PlainTextRendererContrib);
 NotebookRegistry.registerOutputTransform('code', CodeRendererContrib);
 NotebookRegistry.registerOutputTransform('error-trace', ErrorRendererContrib);
+NotebookRegistry.registerOutputTransform('jserror', JSErrorRendererContrib);
 NotebookRegistry.registerOutputTransform('stream-text', StreamRendererContrib);
 NotebookRegistry.registerOutputTransform('stderr', StderrRendererContrib);
 

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

@@ -551,6 +551,7 @@ const _mimeTypeInfo = new Map<string, MimeTypeInfo>([
 	['image/jpeg', { supportedByCore: true }],
 	['text/x-javascript', { alwaysSecure: true, supportedByCore: true }], // secure because rendered as text, not executed
 	['application/x.notebook.error-traceback', { alwaysSecure: true, supportedByCore: true }],
+	['application/x.notebook.error', { alwaysSecure: true, supportedByCore: true }],
 	['application/x.notebook.stream', { alwaysSecure: true, supportedByCore: true, mergeable: true }],
 	['application/x.notebook.stdout', { alwaysSecure: true, supportedByCore: true, mergeable: true }],
 	['application/x.notebook.stderr', { alwaysSecure: true, supportedByCore: true, mergeable: true }],