improve tests and code

packages/overlayscrollbars/src/overlayscrollbars.ts

@@ -37,7 +37,7 @@ export interface OverlayScrollbarsStatic {
   ): OverlayScrollbars;
 
   plugin(plugin: Plugin | Plugin[]): void;
-  valid(osInstance: any): boolean;
+  valid(osInstance: any): osInstance is OverlayScrollbars;
   env(): Environment;
 }
 
@@ -94,19 +94,19 @@ export interface OverlayScrollbars {
   options(): Options;
   options(newOptions: DeepPartial<Options>): Options;
 
-  update(force?: boolean): OverlayScrollbars;
-
-  destroy(): void;
-
-  state(): State;
-
-  elements(): Elements;
-
   on<N extends keyof EventListenerMap>(name: N, listener: EventListener<N>): () => void;
   on<N extends keyof EventListenerMap>(name: N, listener: EventListener<N>[]): () => void;
 
   off<N extends keyof EventListenerMap>(name: N, listener: EventListener<N>): void;
   off<N extends keyof EventListenerMap>(name: N, listener: EventListener<N>[]): void;
+
+  update(force?: boolean): boolean;
+
+  state(): State;
+
+  elements(): Elements;
+
+  destroy(): void;
 }
 
 // eslint-disable-next-line @typescript-eslint/no-redeclare
@@ -115,11 +115,7 @@ export const OverlayScrollbars: OverlayScrollbarsStatic = (
   options?: DeepPartial<Options>,
   eventListeners?: InitialEventListeners
 ) => {
-  const {
-    _getDefaultOptions,
-    _getDefaultInitialization,
-    _addListener: addEnvListener,
-  } = getEnvironment();
+  const { _getDefaultOptions, _getDefaultInitialization, _addListener } = getEnvironment();
   const plugins = getPlugins();
   const targetIsElement = isHTMLElement(target);
   const instanceTarget = targetIsElement ? target : target.target;
@@ -149,10 +145,9 @@ export const OverlayScrollbars: OverlayScrollbarsStatic = (
       currentOptions,
       structureState
     );
-    const update = (changedOptions: DeepPartial<Options>, force?: boolean) => {
+    const update = (changedOptions: DeepPartial<Options>, force?: boolean): boolean =>
       updateStructure(changedOptions, !!force);
-    };
-    const removeEnvListener = addEnvListener(update.bind(0, {}, true));
+    const removeEnvListener = _addListener(update.bind(0, {}, true));
     const destroy = (canceled?: boolean) => {
       removeInstance(instanceTarget);
       removeEnvListener();
@@ -257,10 +252,7 @@ export const OverlayScrollbars: OverlayScrollbarsStatic = (
           }
         );
       },
-      update(force?: boolean) {
-        update({}, force);
-        return instance;
-      },
+      update: (force?: boolean) => update({}, force),
       destroy: destroy.bind(0),
     };
 
@@ -323,13 +315,15 @@ export const OverlayScrollbars: OverlayScrollbarsStatic = (
       ]);
     });
 
-    return instance.update(true);
+    instance.update(true);
+
+    return instance;
   }
   return potentialInstance!;
 };
 
 OverlayScrollbars.plugin = addPlugin;
-OverlayScrollbars.valid = (osInstance: any) => {
+OverlayScrollbars.valid = (osInstance: any): osInstance is OverlayScrollbars => {
   const hasElmsFn = osInstance && (osInstance as OverlayScrollbars).elements;
   const elements = isFunction(hasElmsFn) && hasElmsFn();
   return isPlainObject(elements) && !!getInstance(elements.target);

packages/overlayscrollbars/src/setups/setups.ts

@@ -4,11 +4,11 @@ import type { DeepPartial } from 'typings';
 
 export type SetupElements<T extends Record<string, any>> = [elements: T, destroy: () => void];
 
-export type SetupUpdate<T extends any[]> = (
+export type SetupUpdate<Args extends any[], R> = (
   changedOptions: DeepPartial<Options>,
   force: boolean,
-  ...args: T
-) => void;
+  ...args: Args
+) => R;
 
 export type SetupUpdateCheckOption = <T>(path: string) => [value: T, changed: boolean];
 
@@ -26,8 +26,9 @@ export type SetupState<T extends Record<string, any>> = [
 export type Setup<
   DynamicState,
   StaticState extends Record<string, any> = Record<string, any>,
-  A extends any[] = []
-> = [update: SetupUpdate<A>, state: (() => DynamicState) & StaticState, destroy: () => void];
+  Args extends any[] = [],
+  R = void
+> = [update: SetupUpdate<Args, R>, state: (() => DynamicState) & StaticState, destroy: () => void];
 
 const getPropByPath = <T>(obj: any, path: string): T =>
   obj

packages/overlayscrollbars/src/setups/structureSetup/structureSetup.ts

@@ -68,34 +68,33 @@ const initialStructureSetupUpdateState: StructureSetupState = {
 export const createStructureSetup = (
   target: InitializationTarget,
   options: ReadonlyOptions
-): Setup<StructureSetupState, StructureSetupStaticState> => {
+): Setup<StructureSetupState, StructureSetupStaticState, [], boolean> => {
   const checkOptionsFallback = createOptionCheck(options, {});
   const state = createState(initialStructureSetupUpdateState);
   const [addEvent, removeEvent, triggerEvent] = createEventListenerHub<StructureSetupEventMap>();
   const [getState] = state;
   const [elements, appendStructureElements, destroyElements] = createStructureSetupElements(target);
   const updateStructure = createStructureSetupUpdate(elements, state);
-  const triggerUpdateEvent: (...args: StructureSetupEventMap['u']) => void = (
+  const triggerUpdateEvent: (...args: StructureSetupEventMap['u']) => boolean = (
     updateHints,
     changedOptions,
     force
   ) => {
     const truthyUpdateHints = keys(updateHints).some((key) => updateHints[key]);
-
-    if (truthyUpdateHints || !isEmptyObject(changedOptions) || force) {
+    const changed = truthyUpdateHints || !isEmptyObject(changedOptions) || force;
+    if (changed) {
       triggerEvent('u', [updateHints, changedOptions, force]);
     }
+    return changed;
   };
   const [destroyObservers, appendObserverElements, updateObservers, updateObserversOptions] =
-    createStructureSetupObservers(elements, state, (updateHints) => {
-      triggerUpdateEvent(updateStructure(checkOptionsFallback, updateHints), {}, false);
-    });
+    createStructureSetupObservers(elements, state, (updateHints) =>
+      triggerUpdateEvent(updateStructure(checkOptionsFallback, updateHints), {}, false)
+    );
 
   const structureSetupState = getState.bind(0) as (() => StructureSetupState) &
     StructureSetupStaticState;
-  structureSetupState._addOnUpdatedListener = (listener) => {
-    addEvent('u', listener);
-  };
+  structureSetupState._addOnUpdatedListener = (listener) => addEvent('u', listener);
   structureSetupState._appendElements = () => {
     const { _target, _viewport } = elements;
     const initialScrollLeft = scrollLeft(_target);
@@ -113,7 +112,7 @@ export const createStructureSetup = (
     (changedOptions, force?) => {
       const checkOption = createOptionCheck(options, changedOptions, force);
       updateObserversOptions(checkOption);
-      triggerUpdateEvent(
+      return triggerUpdateEvent(
         updateStructure(checkOption, updateObservers(), force),
         changedOptions,
         !!force

packages/overlayscrollbars/tests/jest-jsdom/overlayscrollbars.test.ts

@@ -0,0 +1,408 @@
+import { DeepPartial } from 'typings';
+import { defaultOptions, Options } from 'options';
+import { assignDeep } from 'support';
+import { OverlayScrollbars as originalOverlayScrollbars } from '../../src/overlayscrollbars';
+
+const bodyElm = document.body;
+const div = document.createElement('div');
+
+bodyElm.append(div);
+
+let OverlayScrollbars = originalOverlayScrollbars;
+
+describe('overlayscrollbars', () => {
+  beforeEach(async () => {
+    jest.resetModules();
+    ({ OverlayScrollbars } = await import('../../src/overlayscrollbars'));
+  });
+
+  afterEach(() => {
+    const instance = OverlayScrollbars(div);
+    if (OverlayScrollbars.valid(instance)) {
+      instance.destroy();
+    }
+  });
+
+  describe('instance', () => {
+    describe('initialization', () => {
+      describe('initialization completed', () => {
+        [div, { target: div }].forEach((init) => {
+          describe(`as ${init === div ? 'element' : 'object'}`, () => {
+            test('without options', () => {
+              const osInstance = OverlayScrollbars(init);
+
+              expect(OverlayScrollbars.valid(osInstance)).toBe(false);
+              expect(div.children.length).toBe(0);
+            });
+
+            test('with empty options', () => {
+              const osInstance = OverlayScrollbars(init, {});
+
+              expect(OverlayScrollbars.valid(osInstance)).toBe(true);
+              expect(div.children.length).not.toBe(0);
+
+              expect(osInstance.options()).not.toBe(defaultOptions);
+              expect(osInstance.options()).toEqual(defaultOptions);
+            });
+
+            test('with custom options', () => {
+              const customOptions: DeepPartial<Options> = {
+                paddingAbsolute: false,
+                showNativeOverlaidScrollbars: true,
+                overflow: {
+                  x: 'hidden',
+                },
+                update: {
+                  ignoreMutation: () => true,
+                  elementEvents: null,
+                },
+                scrollbars: {
+                  pointers: null,
+                  autoHideDelay: 0,
+                },
+              };
+              const osInstance = OverlayScrollbars(init, customOptions);
+
+              expect(OverlayScrollbars.valid(osInstance)).toBe(true);
+              expect(div.children.length).not.toBe(0);
+
+              expect(osInstance.options()).toEqual(assignDeep({}, defaultOptions, customOptions));
+            });
+
+            test('with event listeners', () => {
+              const initialized = jest.fn();
+              const updated = jest.fn();
+              const destroyed = jest.fn();
+              const osInstance = OverlayScrollbars(
+                init,
+                {},
+                {
+                  initialized,
+                  updated,
+                  destroyed,
+                }
+              );
+
+              expect(OverlayScrollbars.valid(osInstance)).toBe(true);
+              expect(div.children.length).not.toBe(0);
+
+              expect(initialized).toHaveBeenCalledTimes(1);
+              expect(initialized).toHaveBeenCalledWith(osInstance);
+
+              expect(updated).toHaveBeenCalledTimes(1);
+              expect(updated).toHaveBeenCalledWith(osInstance, expect.any(Object));
+
+              expect(destroyed).not.toHaveBeenCalled();
+
+              osInstance.destroy();
+
+              expect(destroyed).toHaveBeenCalledTimes(1);
+              expect(destroyed).toHaveBeenCalledWith(osInstance, false);
+            });
+          });
+        });
+      });
+
+      describe('initialization canceled', () => {
+        test('without options', () => {
+          const osInstance = OverlayScrollbars({
+            target: div,
+            cancel: { nativeScrollbarsOverlaid: true },
+          });
+
+          expect(OverlayScrollbars.valid(osInstance)).toBe(false);
+          expect(div.children.length).toBe(0);
+        });
+
+        test('with empty options', () => {
+          const osInstance = OverlayScrollbars(
+            {
+              target: div,
+              cancel: { nativeScrollbarsOverlaid: true },
+            },
+            {}
+          );
+
+          expect(OverlayScrollbars.valid(osInstance)).toBe(false);
+          expect(div.children.length).toBe(0);
+        });
+
+        test('with event listeners', () => {
+          const initialized = jest.fn();
+          const updated = jest.fn();
+          const destroyed = jest.fn();
+          const osInstance = OverlayScrollbars(
+            {
+              target: div,
+              cancel: { nativeScrollbarsOverlaid: true },
+            },
+            {},
+            {
+              initialized,
+              updated,
+              destroyed,
+            }
+          );
+
+          expect(OverlayScrollbars.valid(osInstance)).toBe(false);
+          expect(div.children.length).toBe(0);
+
+          expect(initialized).not.toHaveBeenCalled();
+          expect(updated).not.toHaveBeenCalled();
+          expect(destroyed).toHaveBeenCalledTimes(1);
+          expect(destroyed).toHaveBeenCalledWith(osInstance, true);
+        });
+      });
+    });
+
+    test('options', () => {
+      const customOptions: DeepPartial<Options> = {
+        paddingAbsolute: !defaultOptions.paddingAbsolute,
+        overflow: { x: 'hidden' },
+      };
+      const osInstance = OverlayScrollbars(div, {});
+      expect(osInstance.options()).not.toBe(defaultOptions);
+      expect(osInstance.options()).toEqual(defaultOptions);
+      OverlayScrollbars(div)!.destroy();
+
+      expect(OverlayScrollbars(div, customOptions).options()).toEqual(
+        assignDeep({}, defaultOptions, customOptions)
+      );
+      OverlayScrollbars(div)!.destroy();
+
+      const osInstance2 = OverlayScrollbars(div, {});
+      expect(osInstance2.options(customOptions)).toEqual(
+        assignDeep({}, defaultOptions, customOptions)
+      );
+      expect(osInstance2.options()).toEqual(assignDeep({}, defaultOptions, customOptions));
+    });
+
+    test('on', () => {
+      const onInitialized = jest.fn();
+      const onUpdated = jest.fn();
+      const onUpdated2 = jest.fn();
+      const onDestroyed = jest.fn();
+      const osInstance = OverlayScrollbars(div, {});
+
+      osInstance.on('initialized', onInitialized);
+      osInstance.on('updated', [onUpdated, onUpdated, onUpdated2]);
+      osInstance.on('destroyed', onDestroyed);
+
+      expect(onInitialized).not.toHaveBeenCalled();
+
+      expect(onUpdated).not.toHaveBeenCalled();
+      expect(onUpdated2).not.toHaveBeenCalled();
+
+      osInstance.update();
+      expect(onUpdated).not.toHaveBeenCalled();
+      expect(onUpdated2).not.toHaveBeenCalled();
+
+      osInstance.update(true);
+      expect(onUpdated).toHaveBeenCalledTimes(1);
+      expect(onUpdated2).toHaveBeenCalledTimes(1);
+      expect(onUpdated).toHaveBeenLastCalledWith(osInstance, expect.any(Object));
+      expect(onUpdated2).toHaveBeenLastCalledWith(osInstance, expect.any(Object));
+
+      expect(onDestroyed).not.toHaveBeenCalled();
+      OverlayScrollbars(div)!.destroy();
+      expect(onDestroyed).toHaveBeenCalledTimes(1);
+      expect(onDestroyed).toHaveBeenLastCalledWith(osInstance, false);
+
+      // after destruction no further events are triggered
+      osInstance.update(true);
+      expect(onUpdated).toHaveBeenCalledTimes(1);
+      expect(onUpdated2).toHaveBeenCalledTimes(1);
+    });
+
+    test('off', () => {
+      const onInitialized = jest.fn();
+      const onUpdated = jest.fn();
+      const onUpdated2 = jest.fn();
+      const onDestroyed = jest.fn();
+
+      expect(onInitialized).not.toHaveBeenCalled();
+      const osInstance = OverlayScrollbars(
+        div,
+        {},
+        {
+          initialized: onInitialized,
+          updated: [onUpdated, onUpdated, onUpdated2],
+          destroyed: onDestroyed,
+        }
+      );
+
+      expect(onInitialized).toHaveBeenCalledTimes(1);
+      expect(onInitialized).toHaveBeenLastCalledWith(osInstance);
+
+      expect(onUpdated).toHaveBeenCalledTimes(1);
+      expect(onUpdated2).toHaveBeenCalledTimes(1);
+
+      osInstance.update(true);
+
+      expect(onUpdated).toHaveBeenCalledTimes(2);
+      expect(onUpdated2).toHaveBeenCalledTimes(2);
+
+      osInstance.off('updated', onUpdated2);
+      osInstance.update(true);
+      expect(onUpdated).toHaveBeenCalledTimes(3);
+      expect(onUpdated2).toHaveBeenCalledTimes(2);
+
+      osInstance.on('updated', onUpdated2);
+      osInstance.update(true);
+      expect(onUpdated).toHaveBeenCalledTimes(4);
+      expect(onUpdated2).toHaveBeenCalledTimes(3);
+
+      osInstance.off('updated', [onUpdated, onUpdated2]);
+      osInstance.update(true);
+      expect(onUpdated).toHaveBeenCalledTimes(4);
+      expect(onUpdated2).toHaveBeenCalledTimes(3);
+
+      osInstance.off('destroyed', onDestroyed);
+      expect(onDestroyed).not.toHaveBeenCalled();
+      osInstance.destroy();
+      expect(onDestroyed).not.toHaveBeenCalled();
+    });
+
+    test('state', () => {
+      const osInstance = OverlayScrollbars(div, {});
+      const state = osInstance.state();
+      const stateObj = {
+        overflowEdge: { x: 0, y: 0 },
+        overflowAmount: { x: 0, y: 0 },
+        overflowStyle: { x: '', y: '' },
+        hasOverflow: { x: false, y: false },
+        padding: { t: 0, r: 0, b: 0, l: 0 },
+        paddingAbsolute: false,
+        directionRTL: false,
+        destroyed: false,
+      };
+
+      expect(state).not.toBe(osInstance.state());
+      expect(state).toEqual(osInstance.state());
+      expect(state).toEqual(stateObj);
+
+      osInstance.options({ paddingAbsolute: true });
+      expect(osInstance.state()).toEqual(
+        expect.objectContaining({
+          paddingAbsolute: true,
+        })
+      );
+
+      osInstance.destroy();
+      expect(osInstance.state()).toEqual(
+        expect.objectContaining({
+          destroyed: true,
+        })
+      );
+    });
+
+    test('elements', () => {
+      const osInstance = OverlayScrollbars(div, {});
+      const elements = osInstance.elements();
+      const elementsObj = {
+        target: div,
+        host: div,
+        padding: expect.any(HTMLElement),
+        viewport: expect.any(HTMLElement),
+        content: expect.any(HTMLElement),
+        scrollOffsetElement: expect.any(HTMLElement),
+        scrollEventElement: expect.any(HTMLElement),
+        scrollbarHorizontal: {
+          scrollbar: expect.any(HTMLElement),
+          track: expect.any(HTMLElement),
+          handle: expect.any(HTMLElement),
+          clone: expect.any(Function),
+        },
+        scrollbarVertical: {
+          scrollbar: expect.any(HTMLElement),
+          track: expect.any(HTMLElement),
+          handle: expect.any(HTMLElement),
+          clone: expect.any(Function),
+        },
+      };
+
+      expect(elements).not.toBe(osInstance.elements());
+      // clone function identity is always different
+      expect(
+        assignDeep({}, elements, {
+          scrollbarHorizontal: {
+            clone: null,
+          },
+          scrollbarVertical: {
+            clone: null,
+          },
+        })
+      ).toEqual(
+        assignDeep({}, osInstance.elements(), {
+          scrollbarHorizontal: {
+            clone: null,
+          },
+          scrollbarVertical: {
+            clone: null,
+          },
+        })
+      );
+      expect(elements).toEqual(elementsObj);
+
+      osInstance.destroy();
+
+      expect(elements).toEqual(elementsObj);
+    });
+
+    test('update', () => {
+      const osInstance = OverlayScrollbars(div, {});
+      expect(osInstance.update()).toBe(false);
+      expect(osInstance.update(false)).toBe(false);
+      expect(osInstance.update(true)).toBe(true);
+
+      // host mutation
+      div.style.cursor = 'pointer';
+      expect(osInstance.update()).toBe(true);
+    });
+  });
+
+  describe('static', () => {
+    test('plugin', () => {
+      expect(OverlayScrollbars.plugin).toEqual(expect.any(Function));
+    });
+
+    test('env', () => {
+      const env = OverlayScrollbars.env();
+      const envObj = {
+        scrollbarsSize: { x: 0, y: 0 },
+        scrollbarsOverlaid: { x: true, y: true },
+        scrollbarsHiding: false,
+        rtlScrollBehavior: { i: true, n: false },
+        flexboxGlue: true,
+        cssCustomProperties: false,
+        staticDefaultInitialization: expect.any(Object),
+        staticDefaultOptions: expect.any(Object),
+        getDefaultInitialization: expect.any(Function),
+        setDefaultInitialization: expect.any(Function),
+        getDefaultOptions: expect.any(Function),
+        setDefaultOptions: expect.any(Function),
+      };
+      expect(env).not.toBe(OverlayScrollbars.env());
+      expect(env).toEqual(OverlayScrollbars.env());
+      expect(env).toEqual(envObj);
+    });
+
+    test('valid', () => {
+      expect(OverlayScrollbars.valid(true)).toBe(false);
+      expect(OverlayScrollbars.valid(false)).toBe(false);
+      expect(OverlayScrollbars.valid('')).toBe(false);
+      expect(OverlayScrollbars.valid(123)).toBe(false);
+      expect(OverlayScrollbars.valid({})).toBe(false);
+      expect(OverlayScrollbars.valid(div)).toBe(false);
+      expect(OverlayScrollbars.valid(setTimeout)).toBe(false);
+
+      expect(OverlayScrollbars.valid(OverlayScrollbars(div))).toBe(false);
+
+      const osInstance = OverlayScrollbars(div, {});
+      expect(OverlayScrollbars.valid(osInstance)).toBe(true);
+
+      osInstance.destroy();
+      expect(OverlayScrollbars.valid(osInstance)).toBe(false);
+    });
+  });
+});

packages/overlayscrollbars/tests/jest-jsdom/support/eventListeners.test.ts

@@ -2,6 +2,7 @@ import { createEventListenerHub } from 'support/eventListeners';
 
 type EventMap = {
   onBoolean: [a: boolean, b: string];
+  onString: [a: string];
   onUndefined: [];
 };
 
@@ -10,19 +11,27 @@ describe('eventListeners', () => {
     test('initialization', () => {
       const onBooleanA = jest.fn((a: boolean, b: string) => a + b);
       const onBooleanB = jest.fn();
+      const onString = jest.fn();
       const onUndefined = jest.fn();
       const [, , triggerEvent] = createEventListenerHub<EventMap>({
         onBoolean: [onBooleanA, onBooleanB],
+        onString: [onString, onString], // multiple equal listeners are treated as one
         onUndefined,
       });
       triggerEvent('onBoolean', [true, 'hi']);
+      triggerEvent('onString', ['hi']);
       triggerEvent('onUndefined');
 
       expect(onBooleanA).toHaveBeenCalledTimes(1);
       expect(onBooleanA).toHaveBeenLastCalledWith(true, 'hi');
+
       expect(onBooleanB).toHaveBeenCalledTimes(1);
       expect(onBooleanB).toHaveBeenLastCalledWith(true, 'hi');
 
+      // even though onString was registered twice, its only called once
+      expect(onString).toHaveBeenCalledTimes(1);
+      expect(onString).toHaveBeenLastCalledWith('hi');
+
       expect(onUndefined).toHaveBeenCalledTimes(1);
       expect(onUndefined).toHaveBeenLastCalledWith();
     });
@@ -30,6 +39,7 @@ describe('eventListeners', () => {
     test('addEvent', () => {
       const onBooleanA = jest.fn((a: boolean, b: string) => a + b);
       const onBooleanB = jest.fn();
+      const onString = jest.fn();
       const onUndefinedA = jest.fn();
       const onUndefinedB = jest.fn();
       const [addEvent, , triggerEvent] = createEventListenerHub<EventMap>();
@@ -68,6 +78,14 @@ describe('eventListeners', () => {
       expect(onUndefinedB).toHaveBeenCalledTimes(2);
       expect(onUndefinedB).toHaveBeenLastCalledWith();
 
+      // multiple equal listeners are treated as one
+      addEvent('onString', [onString, onString]);
+      triggerEvent('onString', ['hi']);
+
+      // even though onString was registered twice, its only called once
+      expect(onString).toHaveBeenCalledTimes(1);
+      expect(onString).toHaveBeenLastCalledWith('hi');
+
       const something = jest.fn();
       // @ts-ignore
       addEvent('something', something);
@@ -79,6 +97,7 @@ describe('eventListeners', () => {
     test('removeEvent', () => {
       const onBooleanA = jest.fn();
       const onBooleanB = jest.fn();
+      const onString = jest.fn();
       const onUndefinedA = jest.fn();
       const onUndefinedB = jest.fn();
       const [addEvent, removeEvent, triggerEvent] = createEventListenerHub<EventMap>({
@@ -149,6 +168,17 @@ describe('eventListeners', () => {
       expect(onUndefinedA).toHaveBeenCalledTimes(4);
       expect(onUndefinedB).toHaveBeenCalledTimes(4);
 
+      addEvent('onString', [onString, onString]);
+      triggerEvent('onString', ['hi']);
+
+      expect(onString).toHaveBeenCalledTimes(1);
+
+      // even though onString was registered twice, its treated as a single listener because multiple equal listeners are treated as one
+      removeEvent('onString', onString);
+      triggerEvent('onString', ['hi']);
+
+      expect(onString).toHaveBeenCalledTimes(1);
+
       // @ts-ignore
       const something = jest.fn();
       // @ts-ignore