Merge pull request #93125 from piraces/fix-history-extra-navigations

Fix history entries navigation taking extra navigates in debug console

src/vs/base/common/history.ts

@@ -28,11 +28,17 @@ export class HistoryNavigator<T> implements INavigator<T> {
 	}
 
 	public next(): T | null {
-		return this._navigator.next();
+		if (this._currentPosition() !== this._elements.length - 1) {
+			return this._navigator.next();
+		}
+		return null;
 	}
 
 	public previous(): T | null {
-		return this._navigator.previous();
+		if (this._currentPosition() !== 0) {
+			return this._navigator.previous();
+		}
+		return null;
 	}
 
 	public current(): T | null {
@@ -73,6 +79,15 @@ export class HistoryNavigator<T> implements INavigator<T> {
 		}
 	}
 
+	private _currentPosition(): number {
+		const currentElement = this._navigator.current();
+		if (!currentElement) {
+			return -1;
+		}
+
+		return this._elements.indexOf(currentElement);
+	}
+
 	private _initialize(history: readonly T[]): void {
 		this._history = new Set();
 		for (const entry of history) {

src/vs/base/test/common/history.test.ts

@@ -106,6 +106,40 @@ suite('History Navigator', () => {
 		assert.deepEqual(['2', '3', '1'], toArray(testObject));
 	});
 
+	test('previous returns null if the current position is the first one', () => {
+		const testObject = new HistoryNavigator(['1', '2', '3']);
+
+		testObject.first();
+
+		assert.deepEqual(testObject.previous(), null);
+	});
+
+	test('previous returns object if the current position is not the first one', () => {
+		const testObject = new HistoryNavigator(['1', '2', '3']);
+
+		testObject.first();
+		testObject.next();
+
+		assert.deepEqual(testObject.previous(), '1');
+	});
+
+	test('next returns null if the current position is the last one', () => {
+		const testObject = new HistoryNavigator(['1', '2', '3']);
+
+		testObject.last();
+
+		assert.deepEqual(testObject.next(), null);
+	});
+
+	test('next returns object if the current position is not the last one', () => {
+		const testObject = new HistoryNavigator(['1', '2', '3']);
+
+		testObject.last();
+		testObject.previous();
+
+		assert.deepEqual(testObject.next(), '3');
+	});
+
 	test('clear', () => {
 		const testObject = new HistoryNavigator(['a', 'b', 'c']);
 		assert.equal(testObject.previous(), 'c');