fix: issue #151: delta fallback if one of vectors is null

[GrizliK1988]

Hi @vitalii-andriiovskyi ,

could you please check this one?

Not sure why this issue happens and simply added a fallback. Hope it's fine.

[luchianenco]

any update when this PR can be reviewed and merged?

[vitalii-andriiovskyi]

@luchianenco This PR needs improvements. The fallback should be added to the method difference of CarouselService but not at it's here.

I fixed it. I think I'll publish the library with fix and other improvements within next 3 days. This fix will be in versions of ngx-owl-carousel-o for Angular 10, and later versions.

[GrizliK1988]

Thank you @vitalii-andriiovskyi !

[luchianenco]

@vitalii-andriiovskyi big thank for the fast reply

[vitalii-andriiovskyi]

@GrizliK1988 @luchianenco

Published versions 4.1.0 (for Angular 10) and 5.1.0 (for Angular 11) with fallback. You can install and check whether the issue has gone.