Date filter breaks consistency with Angular

[ilanbiala]

If I have something like this {{day | date:'mediumDate'}} where day could be an empty string '', angular is supposed to produce nothing for invalid values. However, I see undefined NaN, NaN, which goes against Angular's consistent "if the input is invalid, Angular won't throw errors, it will just output nothing." Is that not the case for the date filter?

How can I still get an empty string '' to be outputted? Do I have to add a conditional inside the expression?

[lgalfaso]

I cannot reproduce the issue mentioned here http://plnkr.co/edit/sICy9FhJ2mWbkNvhw5pv?p=preview
Would it be possible to have a plunker that shows the issue?

[ilanbiala]

@lgalfaso sorry the issue is actually when day is an invalid date such as new Date('abc').

[ilanbiala]

@pkozlowski-opensource @lgalfaso thanks for the quick help!