ERROR TypeError: this.scrollEvent.exhaustMap is not a function at InfscrollDirective

[DmytroZamura]

When I scroll on top of the chat window to load previous messages the next error fired: ERROR TypeError: this.scrollEvent.exhaustMap is not a function at InfscrollDirective.push../src/app/chat-app/infscroll.directive.ts.InfscrollDirective.ngAfterViewInit (infscroll.directive.ts:53) at callProviderLifecycles (core.js:18985) at callElementProvidersLifecycles (core.js:18959) at callLifecycleHooksChildrenFirst (core.js:18949) at checkAndUpdateView (core.js:19885) at callViewAction (core.js:20117) at execComponentViewsAction (core.js:20059) at checkAndUpdateView (core.js:19882) at callViewAction (core.js:20117) at execEmbeddedViewsAction (core.js:20080) View_ChatMessageViewComponent_0 @ ChatMessageViewComponent.html:6 proxyClass @ compiler.js:10198 push../node_modules/@angular/core/fesm5/core.js.DebugContext_.logError @ core.js:20732 push../node_modules/@angular/core/fesm5/core.js.ErrorHandler.handleError @ core.js:12680 (anonymous) @ core.js:14926 push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invoke @ zone.js:388 push../node_modules/zone.js/dist/zone.js.Zone.run @ zone.js:138 push../node_modules/@angular/core/fesm5/core.js.NgZone.runOutsideAngular @ core.js:14150 push../node_modules/@angular/core/fesm5/core.js.ApplicationRef.tick @ core.js:14926 (anonymous) @ core.js:14810 push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invoke @ zone.js:388 onInvoke @ core.js:14191 push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invoke @ zone.js:387 push../node_modules/zone.js/dist/zone.js.Zone.run @ zone.js:138 push../node_modules/@angular/core/fesm5/core.js.NgZone.run @ core.js:14105 next @ core.js:14810 schedulerFn @ core.js:10206 push../node_modules/rxjs/_esm5/internal/Subscriber.js.SafeSubscriber.__tryOrUnsub @ Subscriber.js:196 push../node_modules/rxjs/_esm5/internal/Subscriber.js.SafeSubscriber.next @ Subscriber.js:134 push../node_modules/rxjs/_esm5/internal/Subscriber.js.Subscriber._next @ Subscriber.js:77 push../node_modules/rxjs/_esm5/internal/Subscriber.js.Subscriber.next @ Subscriber.js:54 push../node_modules/rxjs/_esm5/internal/Subject.js.Subject.next @ Subject.js:47 push../node_modules/@angular/core/fesm5/core.js.EventEmitter.emit @ core.js:10190 checkStable @ core.js:14160 onLeave @ core.js:14227 onInvokeTask @ core.js:14185 push../node_modules/zone.js/dist/zone.js.ZoneDelegate.invokeTask @ zone.js:420 push../node_modules/zone.js/dist/zone.js.Zone.runTask @ zone.js:188 push../node_modules/zone.js/dist/zone.js.ZoneTask.invokeTask @ zone.js:496 invokeTask @ zone.js:1540 globalZoneAwareCallback @ zone.js:1566

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In my opinion, the reason is with not right calling exhaustMap. My fix is to change ngAfterViewInit from: ngAfterViewInit() { this.scrollEvent = this.obs .pipe( pairwise(), filter(this.isScrollingUpPastThreshold.bind(this))); this.scrollEvent .exhaustMap(() => this.appInfscroll()).subscribe({}); }

on:

ngAfterViewInit() { this.scrollEvent = this.obs .pipe( pairwise(), filter(this.isScrollingUpPastThreshold.bind(this)), exhaustMap(() => this.appInfscroll())).subscribe(); }

This fixed the issue in my local project and the loading of previous messages works fine.

Thanks.

[joseenrique-dev]

This solved my problem too, thanks very much.

[KoldBrewEd]

Thank you for providing the fix, @DmitryZamura . Would you mind creating a pull request?