Make clsx() function available

[webJose]

Describe the problem

I'm improving my router library. Now my router can provide hash routing to Sveltekit projects (configured for path routing), so hash routing on top of Sveltekit's path routing.

Since Sveltekit can use regular anchor elements, and because there is at least one styling library (Bulma) that applies the "active" look not to the anchor element, but to the parent <li> element, I now want to expose the active feature as an attachment.

My issue: This is my TS type for the information required for this "active" feature:

type ActiveState = {
    key?: string | undefined;
    class?: ClassValue | undefined; // <------------------------   HERE!!!
    style?: HTMLAnchorAttributes["style"] | Record<string, string>;
    ariaCurrent?: HTMLAnchorAttributes["aria-current"];
}

I have defined the class property as accepting all values accepted by clsx because my <Link> component simply adds this property value to the array inside the anchor element: <a ... class={[...., activeState?.class]} ...>. Well, in an attachment, I have to do this imperatively with el.classList.

Describe the proposed solution

Allow me to import the clsx() function that is built-in in Svelte, so I can do:

el.classList.add(clsx(activeState?.class));

The alternative would be to explicitly install the clsx NPM package, which would be redundant.

Importance

would make my life easier

[webJose]

Ok, so I looked at the code in Svelte to see if I could PR this to help out. After all, I am the interested party. Seemed only fair.

While browsing the code, I realized (because of the file names): Wait, Svelte is not distributed bundled. So I ran npm ls clsx in my project and voilà: It is there. I CAN do import { clsx } from "clsx"; since it is a mere dependency.

So if you guys wish to keep this open and do it, go for it. I opened this because, by instinct, I thought the Svelte package was bundled.

[longnguyen2004]

It should still be helpful since pnpm doesn't expose transitive dependencies, so you still need to install clsx for such cases

[Conduitry]

I'd be hesitant to do something like this. I suppose we've already tied ourselves to the clsx API, but unless we're really really tying ourselves to that API and that library, re-exporting it from the Svelte runtime seems like a risky addition to the API surface area. If you have both clsx and svelte as dependencies in your project, package managers should by default use the same clsx instance in the direct dependency and as the transitive dependency of svelte.