feat: show warning on pkg fetch error

[nitodeco]

Resolves #19.

Shows warning when package can't be found:

[coderabbitai]

📝 Walkthrough

Walkthrough

The pull request refactors the hover provider for npmx packages by fixing a typo in the package URL function name (npmPacakgeUrl to npmPackageUrl), adding support for the JSR (JavaScript Registry) protocol, and reorganising the protocol validation flow. New logic explicitly handles JSR packages with a warning that they are not available on npmx, and includes fallback messaging when package information retrieval fails. A new jsrPackageUrl utility function is introduced to generate JSR package links.

Possibly related PRs

• refactor: migrate to fast-npm-meta #18: Modifies both src/providers/hover/npmx.ts and src/utils/links.ts with the same npmPacakgeUrl to npmPackageUrl rename and similar hover URL composition changes.
• refactor: enhance version parsing with protocol support and validation #30: Refactors protocol validation in src/providers/hover/npmx.ts using isSupportedProtocol and adjusts version-parsing control flow similarly.
• feat(completion): support 'npm:'-prefixed versions #29: Modifies src/providers/hover/npmx.ts and src/utils/links.ts to update URL construction and version-parsing logic with overlapping control flow changes.

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description check	✅ Passed	The PR description directly references issue #19 and describes the implemented feature: showing a warning when package fetch fails, with supporting visual evidence.
Linked Issues check	✅ Passed	The code changes successfully implement the primary requirement from #19: providing user-facing feedback when package lookup fails by returning a warning hover instead of undefined.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to resolving #19. The modifications to npmx.ts handle JSR protocol support and error feedback, whilst updates to links.ts provide required URL generation utilities.

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✨ Finishing touches

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• Post copyable unit tests in a comment

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[9romise]

Good job! I think we could also prompt users to visit https://jsr.io when a jsr:‑style specifier is detected.

[nitodeco]

@9romise wdyt?

[coderabbitai]

Actionable comments posted: 1

[9romise]

Nice! Thank you! ❤️

[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

src/providers/hover/npmx.ts (1)

46-47: Consider showing feedback for other unsupported protocols.

The PR objectives mention aligning UX with tools like Version Lens that display "not supported" for unsupported registries. Currently, JSR gets explicit feedback, but other unsupported protocols result in no hover at all. For consistency, you might want to show a similar warning for other unsupported protocols.

💡 Optional: Add feedback for unsupported protocols

-    if (!isSupportedProtocol(protocol))
-      return
+    if (!isSupportedProtocol(protocol)) {
+      const unsupportedMd = new MarkdownString('', true)
+      unsupportedMd.isTrusted = true
+      unsupportedMd.appendMarkdown(`$(warning) Protocol "${protocol}" is not supported`)
+      return new Hover(unsupportedMd)
+    }

[coderabbitai]

⚠️ Potential issue | 🟡 Minor

Good error handling for fetch failures, but consider wrapping in try-catch.

This correctly addresses the PR objective of showing feedback when package lookup fails. However, looking at getPackageInfo in the relevant snippets, it returns null for 404 errors but throws for other error types. If a non-404 error occurs (e.g., network timeout, 500), this could result in an unhandled promise rejection.

🛡️ Proposed fix to handle all error cases

-    const pkg = await getPackageInfo(name)
-    if (!pkg) {
+    let pkg: Awaited<ReturnType<typeof getPackageInfo>> = null
+    try {
+      pkg = await getPackageInfo(name)
+    }
+    catch {
+      // Fall through to show error message
+    }
+
+    if (!pkg) {
       const errorMd = new MarkdownString('', true)
 
       errorMd.isTrusted = true
       errorMd.appendMarkdown('$(warning) Unable to fetch package information')
 
       return new Hover(errorMd)
     }

📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change

	const pkg = await getPackageInfo(name)
	if (!pkg) {
	const errorMd = new MarkdownString('', true)
	errorMd.isTrusted = true
	errorMd.appendMarkdown('$(warning) Unable to fetch package information')
	return new Hover(errorMd)
	}
	let pkg: Awaited<ReturnType<typeof getPackageInfo>> = null
	try {
	pkg = await getPackageInfo(name)
	}
	catch {
	// Fall through to show error message
	}
	if (!pkg) {
	const errorMd = new MarkdownString('', true)
	errorMd.isTrusted = true
	errorMd.appendMarkdown('$(warning) Unable to fetch package information')
	return new Hover(errorMd)
	}