When using DatePicker.startDate, previous/next month navigation does not work

[dstj]

Bug description:

When setting [startDate] on a DatePicker as specified in the doc, the navigation the previous or next month no longer work.

When using the alternative navigateTo(), it works.

Note: I can't navigateTo() because I want the datepicker in a ngbPopover (also in the repro)

Link to minimally-working StackBlitz that reproduces the issue:

https://stackblitz.com/edit/angular-xtasaf

Versions of Angular, ng-bootstrap and Bootstrap:

"@angular/core": "^7.2.5",
"@ng-bootstrap/ng-bootstrap": "^4.1.2",
"bootstrap": "^4.3.1",

[maxokorokov]

Hey, @dstj!

As [startDate] is a binding and you're returning a new object every time from the getStartDate() method, you're forcing datepicker to go to this date every time change detection happens.

So if you were to return the same date object, you wouldn't have this issue:

https://stackblitz.com/edit/angular-r72dtz?file=src/app/app.component.ts

However I suppose we should compare the actual start date values inside the datepicker, not rely on object equality in this case.

[dstj]

@maxokorokov, right, I should have suspected that, my bad! I assumed somehow that there would be some kind of equality comparaison on the NgbDateStruct instead of only a reference check.

Thanks.