Fixes #102920

src/vs/editor/common/config/commonEditorConfig.ts

@@ -381,7 +381,7 @@ export abstract class CommonEditorConfiguration extends Disposable implements IC
 					}
 					continue;
 				}
-				if (typeof baseValue === 'object' && typeof subsetValue === 'object') {
+				if (baseValue && typeof baseValue === 'object' && subsetValue && typeof subsetValue === 'object') {
 					if (!this._subsetEquals(baseValue, subsetValue)) {
 						return false;
 					}

src/vs/editor/common/config/editorOptions.ts

@@ -2572,9 +2572,9 @@ class EditorPixelRatio extends ComputedEditorOption<EditorOption.pixelRatio, num
  * Configuration options for quick suggestions
  */
 export interface IQuickSuggestionsOptions {
-	other: boolean;
-	comments: boolean;
-	strings: boolean;
+	other?: boolean;
+	comments?: boolean;
+	strings?: boolean;
 }
 
 export type ValidQuickSuggestionsOptions = boolean | Readonly<Required<IQuickSuggestionsOptions>>;

src/vs/editor/test/common/config/commonEditorConfig.test.ts

@@ -211,4 +211,15 @@ suite('Common Editor Config', () => {
 			strings: false
 		});
 	});
+
+	test('issue #102920: Can\'t snap or split view with JSON files', () => {
+		const config = new TestConfiguration({ quickSuggestions: null! });
+		config.updateOptions({ quickSuggestions: { strings: true } });
+		const actual = <Readonly<Required<IQuickSuggestionsOptions>>>config.options.get(EditorOption.quickSuggestions);
+		assert.deepEqual(actual, {
+			other: true,
+			comments: false,
+			strings: true
+		});
+	});
 });

src/vs/monaco.d.ts

@@ -3557,9 +3557,9 @@ declare namespace monaco.editor {
 	 * Configuration options for quick suggestions
 	 */
 	export interface IQuickSuggestionsOptions {
-		other: boolean;
-		comments: boolean;
-		strings: boolean;
+		other?: boolean;
+		comments?: boolean;
+		strings?: boolean;
 	}
 
 	export type ValidQuickSuggestionsOptions = boolean | Readonly<Required<IQuickSuggestionsOptions>>;