custom element duplicate element name registration

[rspieker]

If a tag name is specified within the rollup config (and not in the .svelte files), that name ends up being specified multiple times (once per .svelte file)

demo repo demonstrating the issue

This may be related to #2417

[Conduitry]

If you're specifying a tag name in the configuration that's passed to the compiler (via the Rollup config), you're saying any component compiled with that configuration should get that tag name, so this is expected.

See also #1884 for another sort of related issue.

It's possible we should provide a way in rollup-plugin-svelte (and svelte-loader) to vary the compiler options based on which file you're compiling, but I'm not sure what that should look like.

[rspieker]

Perhaps my expections are off or unclear, I do expect the specified name to be registered, just not for every subcomponent within the package.
If in a customElement flow, I'd expect only the explicitly named ones to end up as a registered component, not every (sub)component as a separate custom element.

This probably ties in with me working with a lot of smaller packages, each becoming a single component, regardless of its internal structure