Added new skipCss option

[Prinzhorn]

This is WIP (docs, tests) but I wanted to get your approval.

I've added Svelte support to Harp, my favorite static website generator (http://harpjs.com/, sintaxi/terraform#154)

There's one issue though: the generated static HTML (completely without JavaScript) is embedding the generated CSS. This works as expected. However, now if a component needs to be hydrated then the client side JS includes the CSS again (with css: true), which is entirely unnecessary. Using css: false does not work, because compilation happens entirely in-memory (using esbuild stdin). So even if we ignore the fact that I don't need CSS at all for the client bundle, it also wouldn't work because stdin cannot import the external CSS file. There's no filesystem.

So I need an option to compile a Svelte component without any CSS whatsoever.

[EMH333]

I'm not set on the skipCSS name but this feature does make sense. I'm almost tempted to put it under compilerOptions as a difference from the vanilla Svelte options (css could be true, false, or "none" or something), though that would probably be more overhead than it is worth. I've been super busy these past few days but I will give it some more thought

[Prinzhorn]

I'm almost tempted to put it under compilerOptions as a difference from the vanilla Svelte options (css could be true, false, or "none" or something),

Sounds good to me. This refs sveltejs/svelte#7270 then.

I've been super busy these past few days but I will give it some more thought

No worries

[Prinzhorn]

Svelte will get this soon, so I think this project needs to be adjusted for the new possible options as well? And the PR will likely become unnecessary.

sveltejs/svelte#7890

[EMH333]

I've been tracking that PR, great to see some progress! And yeah, the Svelte PR will end up superseding this. I'll leave this open till it gets released though.

Yes, esbuild-svelte will need updates as people start migrating away from the boolean value. none and injected should work out of the box, but external won't. I'll do my best to track the Svelte release and follow up with the fix for this (I feel okay waiting for the official release before fixing it here given that the current version doesn't interfere with the added none feature).

[EMH333]

Svelte released v3.53.0. Will follow up with esbuild-svelte release allowing for 'external' some time in the next week

[EMH333]

Fixed in Svelte and released as esbuild-svelte v0.7.2