From f41273cd7852866dc72dd9430dd289ef62d97b4b Mon Sep 17 00:00:00 2001
From: Johannes Rieken <johannes.rieken@gmail.com>
Date: Wed, 15 Dec 2021 10:42:36 +0100
Subject: [PATCH] add `Event.debouncedListener` as replacement for `debounce`,
 https://github.com/microsoft/vscode/issues/123487

---
 src/vs/base/common/event.ts                   | 35 +++++++++++++++++--
 .../notebook/browser/notebook.contribution.ts |  5 +--
 2 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/src/vs/base/common/event.ts b/src/vs/base/common/event.ts
index 52631be0620..ecbac6597a7 100644
--- a/src/vs/base/common/event.ts
+++ b/src/vs/base/common/event.ts
@@ -119,16 +119,45 @@ export namespace Event {
 		return emitter.event;
 	}
 
+	export function debouncedListener<T, O = T>(event: Event<T>, listener: (data: O) => any, merge: (last: O | undefined, event: T) => O, delay: number = 100, leading: boolean = false): IDisposable {
+
+		let output: O | undefined = undefined;
+		let handle: any = undefined;
+		let numDebouncedCalls = 0;
+
+		return event(cur => {
+			numDebouncedCalls++;
+			output = merge(output, cur);
+
+			if (leading && !handle) {
+				listener(output);
+				output = undefined;
+			}
+
+			clearTimeout(handle);
+			handle = setTimeout(() => {
+				const _output = output;
+				output = undefined;
+				handle = undefined;
+				if (!leading || numDebouncedCalls > 1) {
+					listener(_output!);
+				}
+
+				numDebouncedCalls = 0;
+			}, delay);
+		});
+	}
+
 	/**
-	 * @deprecated DO NOT use, this leaks memory
+	 * @deprecated this leaks memory, {@link debouncedListener} or {@link DebounceEmitter} instead
 	 */
 	export function debounce<T>(event: Event<T>, merge: (last: T | undefined, event: T) => T, delay?: number, leading?: boolean, leakWarningThreshold?: number): Event<T>;
 	/**
-	 * @deprecated DO NOT use, this leaks memory
+	 * @deprecated this leaks memory, {@link debouncedListener} or {@link DebounceEmitter} instead
 	 */
 	export function debounce<I, O>(event: Event<I>, merge: (last: O | undefined, event: I) => O, delay?: number, leading?: boolean, leakWarningThreshold?: number): Event<O>;
 	/**
-	 * @deprecated DO NOT use, this leaks memory
+	 * @deprecated this leaks memory, {@link debouncedListener} or {@link DebounceEmitter} instead
 	 */
 	export function debounce<I, O>(event: Event<I>, merge: (last: O | undefined, event: I) => O, delay: number = 100, leading = false, leakWarningThreshold?: number): Event<O> {
 
diff --git a/src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts b/src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts
index 7a5ea0f7d4f..635ead87134 100644
--- a/src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts
+++ b/src/vs/workbench/contrib/notebook/browser/notebook.contribution.ts
@@ -504,11 +504,12 @@ class NotebookEditorManager implements IWorkbenchContribution {
 
 		// OPEN notebook editor for models that have turned dirty without being visible in an editor
 		type E = IResolvedNotebookEditorModel;
-		this._disposables.add(Event.debounce<E, E[]>(
+		this._disposables.add(Event.debouncedListener<E, E[]>(
 			this._notebookEditorModelService.onDidChangeDirty,
+			this._openMissingDirtyNotebookEditors.bind(this),
 			(last, current) => !last ? [current] : [...last, current],
 			100
-		)(this._openMissingDirtyNotebookEditors, this));
+		));
 
 		// CLOSE notebook editor for models that have no more serializer
 		this._disposables.add(notebookService.onWillRemoveViewType(e => {