I'm the creator of https://htmgo.dev and I'll say that is definitely the biggest issue I've run into with htmx. It's definitely not an overall replacement, you will have to either rebuilt the date picker from scratch in js, or find a vanilla js library
so unfortunately the major downside I see so far is it's fairly hard to find good open source vanilla js libraries for things, as most things seem to be written for react.
other examples include:
- virtualized list
- combobox
Iam using templ https://templ.guide/ in combination with htmx.
I rebuilded various of html components of https://www.patternfly.org/components/all-components/ - but as you mentioned, I also couldnt find good vanilla JS libraries for more complex components - and I dont feel I am capable to build a e.g. battle tested datepicker from scratch.
so unfortunately the major downside I see so far is it's fairly hard to find good open source vanilla js libraries for things, as most things seem to be written for react.
other examples include: - virtualized list - combobox