Here’s a datepicker for Foundation.

https://github.com/najlepsiwebdesigner/foundation-datepicker

Angular UI Bootstrap is CSS agnostic - you can use it with Foundation just fine

I'm aware of that, but there are styling differences between Foundation and Bootstrap.

The Angular-UI implementation, while self-contained, is going to have a different .modal() implementation than Foundation's, so there's always going to be relics in the implementation.

Implementing twice the framework for the same functionality seems a sure fire way to induce headaches.

Your advice isn't wrong, and worked great for a good number of months, but requires ignoring the JS components of Foundation altogether, which somewhat negates the benefits of having a big ol' framework in the first place (IMHO).

I find ignoring the JS component to work great for me - I override the UI Bootstrap templates and adapt it to work how I want.

I've recently done a project with Semantic-UI, and there are still a lot of gocha's with specific nestings you'll have to follow and some ui blocks that don't mix wel, but the worst thing for me are the modals. If you have more than one modal, you will get both modals being triggered at some times, sometimes, you'll get the fade in/out animation 2 or 3 times, etc.

It's still a young project, and imho one of the best looking ones, but there are still a lot of quirks to work out.

I've started shying away from Angular a little because it's not very simple to work with existing JQuery and JavaScript components with having to re-wrap everything in directives (and supporting it when the underlining components change) has become a huge-PIA....

I recently made the same decision.