feat: add peekToLinkedOnly mode (#127)

[pranaygp]

Closes #127

What

Adds a new cssPeek.peekToLinkedOnly setting (boolean, default false). When enabled, CSS Peek's definition search is restricted to stylesheets explicitly referenced from the current source file, rather than the entire workspace.

This is useful in large monorepos where many unrelated stylesheets define the same class name and only the linked ones are relevant.

How

• package.json: registers the new setting.
• client/src/extension.ts: reads the setting and passes it through initializationOptions (the server also picks it up via workspace/configuration, which is the path actually used per request).
• server/src/server.ts: in onDefinition, when the setting is on, parses the current document for stylesheet references and passes the resolved URIs as an allowedUris: Set<string> to findDefinition.
• server/src/core/findDefinition.ts: findSymbols / findDefinition accept an optional allowedUris parameter and skip stylesheet URIs not in the set.
• server/src/utils/linkedStylesheets.ts: new helper that scans the source text for stylesheet references and resolves them against the document's URI.

Supported reference syntaxes

• HTML / templating: <link rel="stylesheet" href="..."> (attribute order agnostic).
• JS / TS / JSX / TSX / Svelte / Vue: import './foo.css', import x from './foo.scss'.
• CSS / SCSS / LESS: @import './foo.css', @import url('./foo.css').

Relative (./, ../) and absolute (/, http://...) paths are resolved against the document URI. Bare specifiers (e.g. import 'normalize.css') are ignored because we don't resolve through node_modules.

Known limitations

Documented as part of the change because the feature is intentionally a simple string-based heuristic:

• No CSS-in-JS detection (styled-components, emotion, vanilla-extract, etc.).
• No Sass @use / @forward (@import only).
• No dynamic imports (import('./foo.css')).
• No bundler alias resolution (e.g. webpack @/styles/foo.css, TS path mappings).
• No bare specifier / node_modules resolution.
• No following of transitive @imports — only stylesheets directly referenced by the current source are searched. Selectors defined in a transitively @imported file will not be found.
• No <style src="..."> (Vue SFC sugar).

When the setting is false (the default), behaviour is unchanged.

Tests

Adds tests/src/linkedOnly.test.ts with:

• An integration test using a new fixture (linked.html links linked.css; unlinked.css exists but is not linked). Verifies that with the setting off both files match, and with the linked-only filter on only linked.css is searched.
• Unit tests for the parser covering JS imports, CSS @import, and <link> tags without rel="stylesheet".

Verification

• yarn build — clean.
• yarn test — 31 passing (24 prior + 7 new).
• yarn lint — clean.
• yarn prettier — clean for all files touched by this PR (pre-existing warnings in unrelated files are not addressed here).

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds a cssPeek.peekToLinkedOnly setting so definition lookup can be restricted to stylesheets directly referenced by the current document.

Changes:

• Registers and passes through the new peekToLinkedOnly configuration.
• Adds linked stylesheet parsing and URI filtering in definition lookup.
• Adds fixtures and tests for linked-only behavior and parser coverage.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
package.json	Adds the new extension setting.
client/src/extension.ts	Reads and forwards the setting to language server initialization.
server/src/server.ts	Applies linked-only filtering during definition requests.
server/src/core/findDefinition.ts	Adds optional URI allow-list filtering.
server/src/utils/linkedStylesheets.ts	Implements stylesheet reference detection and URI resolution.
tests/src/linkedOnly.test.ts	Adds tests for linked-only filtering and parser behavior.
tests/fixture/linked.html, linked.css, unlinked.css	Adds test fixture files for linked-only lookup.

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[pranaygp]

Fixed in c5bb2d3. Tightened the import regex with a negative lookahead \bimport\b(?!\s*\() (and excluded (/) from the inter-token char class) so dynamic import('./foo.css') calls are no longer matched. Added a unit test ("ignores dynamic import() expressions") that confirms import('./theme.css') and await import("./other.scss") are skipped while a sibling import './static.css' is still included.

[pranaygp]

Fixed in c5bb2d3. resolveStylesheetUri now strips ?query and #fragment from the local ref before constructing the URI (ref.replace(/[?#].*$/, "")), so cache-busted and fragment-qualified references resolve to the same file URI the stylesheet map is keyed by. The import / @import regexes were also widened to tolerate a trailing ?…/#… after the extension so the suffix doesn't prevent matching in the first place. Added a unit test ("strips query strings and fragments from local refs") covering both ./app.css?v=1 and ./themed.scss#dark.