| import { act, renderHook } from '@testing-library/react-hooks'; |
| import { Subject } from 'rxjs'; |
| import * as useIsomorphicLayoutEffect from '../src/useIsomorphicLayoutEffect'; |
| import useObservable, { Observable } from '../src/useObservable'; |
|
|
| const setUp = (observable: Observable<any>, initialValue?: any) => |
| renderHook(() => useObservable(observable, initialValue)); |
|
|
| it('should init to initial value provided', () => { |
| const subject$ = new Subject(); |
| const { result } = setUp(subject$, 123); |
|
|
| expect(result.current).toBe(123); |
| }); |
|
|
| it('should init to undefined if not initial value provided', () => { |
| const subject$ = new Subject(); |
| const { result } = setUp(subject$); |
|
|
| expect(result.current).toBeUndefined(); |
| }); |
|
|
| it('should return latest value of observables', () => { |
| const subject$ = new Subject(); |
| const { result } = setUp(subject$, 123); |
|
|
| act(() => { |
| subject$.next(125); |
| }); |
| expect(result.current).toBe(125); |
|
|
| act(() => { |
| subject$.next(300); |
| subject$.next(400); |
| }); |
| expect(result.current).toBe(400); |
| }); |
|
|
| it('should use layout effect to subscribe synchronously', async () => { |
| const subject$ = new Subject(); |
| const spy = jest.spyOn(useIsomorphicLayoutEffect, 'default'); |
|
|
| expect(spy).toHaveBeenCalledTimes(0); |
|
|
| setUp(subject$, 123); |
|
|
| expect(spy).toHaveBeenCalledTimes(1); |
| }); |
|
|
| it('should subscribe to observable only once', () => { |
| const subject$ = new Subject(); |
| const spy = jest.spyOn(subject$, 'subscribe'); |
| expect(spy).not.toHaveBeenCalled(); |
|
|
| setUp(subject$, 123); |
|
|
| expect(spy).toHaveBeenCalledTimes(1); |
|
|
| act(() => { |
| subject$.next('a'); |
| }); |
|
|
| act(() => { |
| subject$.next('b'); |
| }); |
|
|
| expect(spy).toHaveBeenCalledTimes(1); |
| }); |
|
|
| it('should return updated value when observable changes', () => { |
| const subject$ = new Subject(); |
| const { result } = setUp(subject$); |
| expect(result.current).toBeUndefined(); |
|
|
| act(() => { |
| subject$.next('foo'); |
| }); |
| expect(result.current).toBe('foo'); |
|
|
| act(() => { |
| subject$.next('bar'); |
| }); |
| expect(result.current).toBe('bar'); |
| }); |
|
|
| it('should unsubscribe from observable', () => { |
| const subject$ = new Subject(); |
| const unsubscribeMock = jest.fn(); |
| subject$.subscribe = jest.fn().mockReturnValue({ |
| unsubscribe: unsubscribeMock, |
| }); |
|
|
| const { unmount } = setUp(subject$); |
| expect(unsubscribeMock).not.toHaveBeenCalled(); |
|
|
| act(() => { |
| subject$.next('foo'); |
| }); |
| expect(unsubscribeMock).not.toHaveBeenCalled(); |
|
|
| act(() => { |
| subject$.next('bar'); |
| }); |
| expect(unsubscribeMock).not.toHaveBeenCalled(); |
|
|
| unmount(); |
| expect(unsubscribeMock).toHaveBeenCalledTimes(1); |
| }); |
|
|
