prettier import { expect } from 'chai' ; import { observableMatcher } from '../helpers/observableMatcher' ; import { of , Observable } from 'rxjs' ; import { defaultIfEmpty , mergeMap , take } from 'rxjs/operators' ; import { TestScheduler } from 'rxjs/testing' ; test describe ( 'defaultIfEmpty' , ( ) => { let testScheduler ; beforeEach ( ( ) => { testScheduler = new TestScheduler ( observableMatcher ) ; } ) ; it ( 'should return the Observable if not empty with a default value' , ( ) => { testScheduler . run ( ( { hot , expectObservable , expectSubscriptions } ) => { const e1 = hot ( '  --------|' ) ; const e1subs = '  ^-------!' ; const expected = '--------(x|)' ; expectObservable ( e1 . pipe ( defaultIfEmpty ( 42 ) ) ) . toBe ( expected , { x : 42 } ) ; expectSubscriptions ( e1 . subscriptions ) . toBe ( e1subs ) ; } ) ; } ) ; it ( 'should return the argument if Observable is empty' , ( ) => { testScheduler . run ( ( { cold , expectObservable , expectSubscriptions } ) => { const e1 = cold ( ' |' ) ; const e1subs = '  (^!)' ; const expected = '(x|)' ; expectObservable ( e1 . pipe ( defaultIfEmpty ( 'x' ) ) ) . toBe ( expected ) ; expectSubscriptions ( e1 . subscriptions ) . toBe ( e1subs ) ; } ) ; } ) ; it ( 'should return the Observable if not empty with a default value' , ( ) => { testScheduler . run ( ( { hot , expectObservable , expectSubscriptions } ) => { const e1 = hot ( '  --a--b--|' ) ; const e1subs = '  ^-------!' ; const expected = '--a--b--|' ; expectObservable ( e1 . pipe ( defaultIfEmpty ( 'x' ) ) ) . toBe ( expected ) ; expectSubscriptions ( e1 . subscriptions ) . toBe ( e1subs ) ; } ) ; } ) ; it ( 'should allow undefined as a default value' , ( ) => { testScheduler . run ( ( { hot , expectObservable , expectSubscriptions } ) => { const e1 = hot ( '  --------|' ) ; const e1subs = '  ^-------!' ; const expected = '--------(U|)' ; expectObservable ( e1 . pipe ( defaultIfEmpty ( undefined ) ) ) . toBe ( expected , { U : undefined } ) ; expectSubscriptions ( e1 . subscriptions ) . toBe ( e1subs ) ; } ) ; } ) ; it ( 'should allow unsubscribing early and explicitly' , ( ) => { testScheduler . run ( ( { hot , expectObservable , expectSubscriptions } ) => { const e1 = hot ( '  --a--b--|' ) ; const e1subs = '  ^---!    ' ; const expected = '--a--    ' ; const unsub = '   ----!    ' ; const result = e1 . pipe ( defaultIfEmpty ( 'x' ) ) ; expectObservable ( result , unsub ) . toBe ( expected ) ; expectSubscriptions ( e1 . subscriptions ) . toBe ( e1subs ) ; } ) ; } ) ; it ( 'should not break unsubscription chains when unsubscribed explicitly' , ( ) => { testScheduler . run ( ( { hot , expectObservable , expectSubscriptions } ) => { const e1 = hot ( '  --a--b--|' ) ; const e1subs = '  ^---!    ' ; const expected = '--a--    ' ; const unsub = '   ----!    ' ; const result = e1 . pipe ( mergeMap ( ( x ) => of ( x ) ) , defaultIfEmpty ( 'x' ) , mergeMap ( ( x ) => of ( x ) ) ) ; expectObservable ( result , unsub ) . toBe ( expected ) ; expectSubscriptions ( e1 . subscriptions ) . toBe ( e1subs ) ; } ) ; } ) ; it ( 'should error if the Observable errors' , ( ) => { testScheduler . run ( ( { cold , expectObservable , expectSubscriptions } ) => { const e1 = cold ( ' #' ) ; const e1subs = '  (^!)' ; const expected = '#' ; expectObservable ( e1 . pipe ( defaultIfEmpty ( 'x' ) ) ) . toBe ( expected ) ; expectSubscriptions ( e1 . subscriptions ) . toBe ( e1subs ) ; } ) ; } ) ; it ( 'should stop listening to a synchronous observable when unsubscribed' , ( ) => { const sideEffects = [ ] ; const synchronousObservable = new Observable ( ( subscriber ) => { for ( let i = 0 ; ! subscriber . closed && i < 10 ; i ++ ) { sideEffects . push ( i ) ; subscriber . next ( i ) ; } } ) ; synchronousObservable . pipe ( defaultIfEmpty ( 0 ) , take ( 3 ) ) . subscribe ( ( ) => { } ) ; expect ( sideEffects ) . to . deep . equal ( [ 0 , 1 , 2 ] ) ; } ) ; } ) ;