chore: provide proper public type for parseCss result

[manuel3108]

Currently, the newly introduced parseCss from svelte/compiler returns Omit<AST.CSS.StyleSheet, 'attributes' | 'content'>. If you try to work with this in external tooling, everywhere where you pass around the result of this method, you need to use that type as well, which is quite cumbersome. (I'm trying to integrate this into sv to get rid of a workaround)

This creates a new type in the CSS AST to differentiate between one stylesheet only having the roles, and one beeing the full one that is used in parse itself. Im 100% open on the name of the new type or any better ideas.

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[changeset-bot]

🦋 Changeset detected

Latest commit: e7923df

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

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svelte	Patch

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[svelte-docs-bot]

Preview: https://svelte-dev-git-preview-svelte-17654-svelte.vercel.app/

[github-actions]

Playground

pnpm add https://pkg.pr.new/svelte@17654

[Rich-Harris]

I think we made a mistake by having two things with the same type — even though you're unlikely to need to discriminate between them, it feels like it defeats the object of having a type in the first place. What if it was this instead?

export interface StyleSheetFile extends BaseNode {
  type: 'StyleSheetFile';
  children: Array<Atrule | Rule>;
}

export interface StyleSheet extends BaseNode {
  type: 'StyleSheet';
  children: Array<Atrule | Rule>;
  attributes: any[]; // TODO
  content: {
    start: number;
    end: number;
    styles: string;
    /** Possible comment atop the style tag */
    comment: AST.Comment | null;
  };
}