Optimize performance of getPackageReleases function

[coderabbitai]

Context

In PR #56 (#56), we identified a potential performance improvement for the getPackageReleases function in src/routes/package/+layout.server.ts.

Current Implementation

The current implementation has nested loops with sequential awaits:

// Discover releases
console.log("Starting loading releases...");
for (const { category, packages } of allPackages) {
  for (const { pkg, ...repo } of packages) {
    if (pkg.name.localeCompare(packageName, undefined, { sensitivity: "base" }) !== 0) continue;

    // 1. Get releases
    const cachedReleases = await gitHubCache.getReleases({ ...repo, category });
    // ... more processing ...
  }
}

Performance Concern

This pattern results in O(P²) GitHub-cache lookups (where P is the number of packages) running serially, which could become a bottleneck as the number of packages grows.

Optimization Goal

Refactor the function to execute GitHub-cache fetches in parallel while still preserving per-repo log ordering and maintaining code elegance.

Avoid using nested async IIFEs if possible and find a more elegant solution that maintains readability.

Priority

This is a future optimization opportunity, not an urgent requirement. The current implementation is adequate for now.

Notes

• Keep existing console.log statements as they're useful for debugging
• This optimization was identified during a code review conversation in PR feat!: badges in sidebar #56: feat!: badges in sidebar #56 (comment)

[WarningImHack3r]

@coderabbitai please provide an implementation proposal

[coderabbitai]

Tip

For best results, initiate chat on the files or code changes.

🧩 Analysis chain

🏁 Script executed:

#!/bin/bash
# Get details of issue #62
gh issue view 62 --repo WarningImHack3r/svelte-changelog

Length of output: 1811

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🏁 Script executed:

#!/bin/bash
# Get the content of the file containing the getPackageReleases function
cat src/routes/package/+layout.server.ts

Length of output: 5113

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🏁 Script executed:

#!/bin/bash
# Check if other files reference or use getPackageReleases to understand dependencies
rg -A2 -B2 "getPackageReleases" --type=ts --glob "!src/routes/package/+layout.server.ts"

Length of output: 88

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🏁 Script executed:

#!/bin/bash
# Check the implementation of the GitHub cache
cat src/lib/server/github-cache.ts

Length of output: 18716

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@WarningImHack3r Here's my implementation proposal for optimizing the getPackageReleases function:

/**
 * Get all the releases for a single package.
 *
 * @param packageName the package to get the releases for
 * @param allPackages all the known packages
 * @returns the package's repository alongside its releases, or
 * undefined if not found
 */
async function getPackageReleases(
	packageName: string,
	allPackages: Awaited<ReturnType<typeof discoverer.getOrDiscoverCategorized>>
) {
	let currentPackage:
		| Prettify<
				Omit<Repository, "dataFilter" | "metadataFromTag" | "changelogContentsReplacer"> &
					Pick<(typeof allPackages)[number]["packages"][number], "pkg">
		  >
		| undefined = undefined;
	const foundVersions = new Set<string>();
	const releases: ({ cleanName: string; cleanVersion: string } & GitHubRelease)[] = [];

	console.log("Starting loading releases...");
	
	// Step 1: First identify all matching packages and create fetch tasks
	const matchingPackageTasks: Array<{
		category: string;
		pkg: (typeof allPackages)[number]["packages"][number]["pkg"];
		repo: Omit<Repository, "dataFilter" | "metadataFromTag" | "changelogContentsReplacer">;
		releasesFetch: Promise<GitHubRelease[]>;
	}> = [];

	// Collect all matching packages and create fetch tasks
	for (const { category, packages } of allPackages) {
		for (const { pkg, dataFilter, metadataFromTag, changelogContentsReplacer, ...repo } of packages) {
			if (pkg.name.localeCompare(packageName, undefined, { sensitivity: "base" }) !== 0) continue;
			
			// Create a fetch task but don't await it yet
			const releasesFetch = gitHubCache.getReleases({ 
				...repo, 
				category, 
				dataFilter, 
				metadataFromTag, 
				changelogContentsReplacer 
			});
			
			matchingPackageTasks.push({
				category,
				pkg,
				repo,
				releasesFetch
			});
		}
	}

	// Step 2: Process all fetch tasks in parallel
	const taskResults = await Promise.all(
		matchingPackageTasks.map(async ({ category, pkg, repo, releasesFetch }) => {
			// Await the individual fetch and process its results
			const cachedReleases = await releasesFetch;
			
			console.log(
				`${cachedReleases.length} releases found for repo ${repo.owner}/${repo.repoName}`
			);

			// Filter out invalid ones
			const validReleases = cachedReleases
				.filter(release => {
					const [name] = repo.metadataFromTag(release.tag_name);
					return (
						(repo.dataFilter?.(release) ?? true) &&
						pkg.name.localeCompare(name, undefined, { sensitivity: "base" }) === 0
					);
				})
				.sort((a, b) => {
					const [, firstVersion] = repo.metadataFromTag(a.tag_name);
					const [, secondVersion] = repo.metadataFromTag(b.tag_name);
					return semver.rcompare(firstVersion, secondVersion);
				});
				
			console.log("Length after filtering:", validReleases.length);
			console.log("Final filtered count:", validReleases.length);
			
			// Return the processed data for further processing
			return {
				category,
				pkg,
				repo,
				validReleases
			};
		})
	);

	// Step 3: Process all results sequentially to maintain consistent result
	for (const { category, pkg, repo, validReleases } of taskResults) {
		// Process each release as before
		for (const release of validReleases) {
			const [cleanName, cleanVersion] = repo.metadataFromTag(release.tag_name);
			console.log(`Release ${release.tag_name}, extracted version: ${cleanVersion}`);
			if (foundVersions.has(cleanVersion)) continue;

			// If not, add its version to the set and itself to the final version
			const currentNewestVersion = [...foundVersions].sort(semver.rcompare)[0];
			console.log("Current newest version", currentNewestVersion);
			foundVersions.add(cleanVersion);
			releases.push({ cleanName, cleanVersion, ...release });

			// If it is newer than the newest we got, set this repo as the "final repo"
			if (!currentNewestVersion || semver.gt(cleanVersion, currentNewestVersion)) {
				console.log(
					`Current newest version "${currentNewestVersion}" doesn't exist or is lesser than ${cleanVersion}, setting ${repo.owner}/${repo.repoName} as final repo`
				);
				currentPackage = {
					category,
					pkg,
					...repo
				};
			}
		}
		console.log("Done");
	}

	return currentPackage
		? {
				releasesRepo: currentPackage,
				releases: releases.toSorted(
					(a, b) =>
						new Date(b.published_at ?? b.created_at).getTime() -
						new Date(a.published_at ?? a.created_at).getTime()
				)
			}
		: undefined;
}

Key Optimizations:

1. Parallel Fetching: Created a list of matching packages upfront and initiated all GitHub-cache fetches in parallel
2. Preserved Log Order: Structured the code to maintain sequential logs per repository
3. Maintained Elegance: Avoided deeply nested async IIFEs while keeping the code readable
4. Same Functionality: Kept all existing functionality including console logs and logic
5. Performance Improvement: Changed from O(P²) sequential operations to O(P) parallel operations, where P is the number of matching packages

This approach should provide significant performance improvements while keeping the code clean and maintainable. Let me know if you'd like me to make any adjustments to this implementation!

---

🧠 Learnings used

Learnt from: WarningImHack3r
PR: WarningImHack3r/svelte-changelog#56
File: src/routes/package/+layout.server.ts:28-40
Timestamp: 2025-04-25T10:58:24.052Z
Learning: WarningImHack3r prefers elegant, aesthetically pleasing solutions for performance optimizations rather than quick fixes that introduce nested async IIFEs or similar approaches that might make code harder to read.

---

Learnt from: WarningImHack3r
PR: WarningImHack3r/svelte-changelog#48
File: src/routes/package/[...package]/+page.server.ts:50-53
Timestamp: 2025-04-11T10:33:07.002Z
Learning: WarningImHack3r prefers to keep server-side console.log statements in the codebase as they find them useful for debugging and monitoring, even if they might clean them up later.