Infinite list with listenWindowScroll doesn't work most of the time

[dabide]

Issue type

I'm submitting a ... (check one with "x")

• [ x] bug report
• feature request

Issue description

Current behavior:

Using nbInfiniteList in combination with listenWindowScroll almost always results in the following error, which results in NbInfiniteListDirective not receiving any scroll events.

ERROR TypeError: Cannot read property 'nativeElement' of undefined
    at NbLayoutComponent.getDimensions (index.js:10644)
    at SafeSubscriber._next (index.js:10539)
    at SafeSubscriber.__tryOrUnsub (Subscriber.js:183)
    at SafeSubscriber.next (Subscriber.js:122)
    at Subscriber._next (Subscriber.js:72)
    at Subscriber.next (Subscriber.js:49)
    at TakeUntilSubscriber._next (Subscriber.js:72)
    at TakeUntilSubscriber.next (Subscriber.js:49)
    at Subject.next (Subject.js:39)
    at Observable._subscribe (index.js:2134)

It probably is some kind of race condition, but I can't find out where.

Expected behavior:

Infinite scroll with listenWindowScroll should work as advertised.

Steps to reproduce:

Just refresh https://www.akveo.com/ngx-admin/pages/layout/infinite-list a couple of times, and the error message will show in the console.

OS: Windows 10/Chrome and Ubuntu/Firefox

[jrasm91]

1. scrollableContainerRef is a ViewChild() of LayoutComponent here
2. getDimensions() is somehow called before ngAfterViewInit(), meaning that the scrollableContainerRef hasn't been loaded/set yet. This causes the cannot read property 'nativeElement' of undefined error.
3. I believe this is caused because of this line here.

If the subscription in 3. was setup in ngAfterViewInit() I believe it would fix the issue.

[jrasm91]

Removing windowMode from <nb-layout>, per this comment also seemed to fix the issue for me.

[evtkhvch]

Fixed in #2949