refactor: derivedConstOnceDefined

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

@@ -614,6 +614,6 @@ export function latestChangedValue<T extends IObservable<any>[]>(owner: DebugOwn
  * However, if the value is not undefined, it is cached and will not be recomputed anymore.
  * In that case, the derived will unsubscribe from its dependencies.
 */
-export function getIfDefined<T>(owner: DebugOwner, fn: (reader: IReader) => T): IObservable<T | undefined> {
+export function derivedConstOnceDefined<T>(owner: DebugOwner, fn: (reader: IReader) => T | undefined): IObservable<T | undefined> {
 	return derivedObservableWithCache<T | undefined>(owner, (reader, lastValue) => lastValue ?? fn(reader));
 }

src/vs/editor/browser/widget/diffEditor/diffEditorOptions.ts

@@ -4,7 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 
 import { IObservable, ISettableObservable, derived, observableFromEvent, observableValue } from 'vs/base/common/observable';
-import { getIfDefined } from 'vs/base/common/observableInternal/utils';
+import { derivedConstOnceDefined } from 'vs/base/common/observableInternal/utils';
 import { Constants } from 'vs/base/common/uint';
 import { DiffEditorViewModel, DiffState } from 'vs/editor/browser/widget/diffEditor/diffEditorViewModel';
 import { diffEditorDefaultOptions } from 'vs/editor/common/config/diffEditor';
@@ -93,12 +93,12 @@ export class DiffEditorOptions {
 	}
 
 	private readonly shouldRenderInlineViewInSmartMode = this._model
-		.map(this, model => getIfDefined(this, reader => {
-			const diffs = model?.diff.read(reader);
-			return diffs ? isSimpleDiff(diffs) : undefined;
-		}))
-		.flatten()
-		.map(this, v => !!v);
+		.map(this, model =>
+			derivedConstOnceDefined(this, reader => {
+				const diffs = model?.diff.read(reader);
+				return diffs ? isSimpleDiff(diffs) : undefined;
+			}).map(this, v => !!v)
+		).flatten();
 }
 
 function isSimpleDiff(diff: DiffState): boolean {