Observables: More owners

Author: hediet

src/vs/base/common/observableInternal/derived.ts

@@ -19,8 +19,8 @@ export const defaultEqualityComparer: EqualityComparer<any> = (a, b) => a === b;
  * {@link computeFn} should start with a JS Doc using `@description` to name the derived.
  */
 export function derived<T>(computeFn: (reader: IReader) => T): IObservable<T>;
-export function derived<T>(owner: object, computeFn: (reader: IReader) => T): IObservable<T>;
-export function derived<T>(computeFnOrOwner: ((reader: IReader) => T) | object, computeFn?: ((reader: IReader) => T) | undefined): IObservable<T> {
+export function derived<T>(owner: Owner, computeFn: (reader: IReader) => T): IObservable<T>;
+export function derived<T>(computeFnOrOwner: ((reader: IReader) => T) | Owner, computeFn?: ((reader: IReader) => T) | undefined): IObservable<T> {
 	if (computeFn !== undefined) {
 		return new Derived(
 			new DebugNameData(computeFnOrOwner, undefined, computeFn),

src/vs/base/common/observableInternal/utils.ts

@@ -404,9 +404,9 @@ export class KeepAliveObserver implements IObserver {
 	}
 }
 
-export function derivedObservableWithCache<T>(computeFn: (reader: IReader, lastValue: T | undefined) => T): IObservable<T> {
+export function derivedObservableWithCache<T>(owner: Owner, computeFn: (reader: IReader, lastValue: T | undefined) => T): IObservable<T> {
 	let lastValue: T | undefined = undefined;
-	const observable = derived(reader => {
+	const observable = derived(owner, reader => {
 		lastValue = computeFn(reader, lastValue);
 		return lastValue;
 	});

src/vs/editor/browser/widget/multiDiffEditor/multiDiffEditorWidgetImpl.ts

@@ -95,7 +95,7 @@ export class MultiDiffEditorWidgetImpl extends Disposable {
 
 	private readonly _totalHeight = this._viewItems.map(this, (items, reader) => items.reduce((r, i) => r + i.contentHeight.read(reader) + this._spaceBetweenPx, 0));
 	public readonly activeDiffItem = derived(this, reader => this._viewItems.read(reader).find(i => i.template.read(reader)?.isFocused.read(reader)));
-	public readonly lastActiveDiffItem = derivedObservableWithCache<VirtualizedViewItem | undefined>((reader, lastValue) => this.activeDiffItem.read(reader) ?? lastValue);
+	public readonly lastActiveDiffItem = derivedObservableWithCache<VirtualizedViewItem | undefined>(this, (reader, lastValue) => this.activeDiffItem.read(reader) ?? lastValue);
 	public readonly activeControl = derived(this, reader => this.lastActiveDiffItem.read(reader)?.template.read(reader)?.editor);
 
 	private readonly _contextKeyService = this._register(this._parentContextKeyService.createScoped(this._element));