use trackBy to prevent full DOM refresh and performance improvement

[volser]

[ ] Bug report 
[x] Feature request
[ ] Support request => Please do not submit a support request here, please ask on https://stackoverflow.com/

I noticed, when I d&d events DOM are totally refreshed, maybe use trackBy to prevent full DOM refresh and performance improvement?
http://recordit.co/yC4LF8jqFT

[mattlewis92]

I've considered this before as well. The problem is that events have no unique id property to track by, do you have any idea if the value returned by the track by function can be an object i.e. the event itself?

[volser]

I believe, by default angular uses object to identify item.

default:
const trackByIdentity = (index: number, item: any) => item;
https://github.com/angular/angular/blob/c8a1a14b87e5907458e8e87021e47f9796cb3257/packages/core/src/change_detection/differs/default_iterable_differ.ts

So you can add id property (optional) to event object, like fullcalendar did
https://fullcalendar.io/docs/event_data/Event_Object/

and (index: number, item: any) => item.id ? item.id : item;

[mattlewis92]

Please give 0.23.3 a go, everything should now use ngFor's. Thanks for the suggestion! 😄