Optimize hot paths: filter complexity, database queries, event loop blocking, and caching

[Copilot]

Identified and fixed performance bottlenecks across filtering, ID generation, database queries, HTTP caching, and event handling.

Changes

• filter.ts: O(n²) → O(n) complexity

  • Replace object spread + delete with reduce for single-pass filtering
  • Use Set for O(1) lookups vs O(n) array.includes()
  • Trim whitespace consistently on include/exclude arrays

• snowflake.ts: Event loop blocking → async wait

  • Replace busy-wait while loop with setTimeout to prevent blocking
  • Fix delay calculation race condition

• lists/route.ts: In-memory filtering → database queries

  • Move search filtering to Prisma where clauses
  • Reduce random fetching from MAX_LIMIT (100) to requested limit
  • Add pagination support to getAuthorLists and getRandomLists

• avatars/[user]/route.ts: Add 1-hour HTTP cache

  • Replace no-cache headers with Cache-Control: public, max-age=3600

• useWindowDimensions.ts: Debounce resize events (150ms)

  • Prevent excessive re-renders during window resizing

Example: Filter optimization

// Before: O(n²) with object mutation
const filtered = { ...object };
exclude.forEach(field => delete filtered[field.trim()]);

// After: O(n) with Set lookup
const excludeSet = new Set(exclude.map(f => f.trim()));
return Object.keys(object).reduce((acc, key) => {
  if (!excludeSet.has(key)) acc[key] = object[key];
  return acc;
}, {});

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• checkpoint.prisma.io
  • Triggering command: /usr/local/bin/node /usr/local/bin/node /home/REDACTED/work/Tenli/Tenli/node_modules/prisma/build/child {"product":"prisma","version":"6.6.0","cli_install_type":"local","information":"","local_timestamp":"2025-12-28T21:19:41Z","project_hash":"9a9085a5","cli_path":"/home/REDACTED/work/Tenli/Tenli/node_modules/.bin/prisma","cli_path_hash":"d483f808","endpoint": (dns block)
  • Triggering command: /usr/local/bin/node /usr/local/bin/node /home/REDACTED/work/Tenli/Tenli/node_modules/prisma/build/child {"product":"prisma","version":"6.6.0","cli_install_type":"local","information":"","local_timestamp":"2025-12-28T21:19:41Z","project_hash":"9a9085a5","cli_path":"/home/REDACTED/work/Tenli/Tenli/node_modules/.bin/prisma","cli_path_hash":"d483f808","endpoint": -name (dns block)
• fonts.googleapis.com
  • Triggering command: /usr/local/bin/node /usr/local/bin/node /home/REDACTED/work/Tenli/Tenli/node_modules/next/dist/compiled/jest-worker/processChild.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

Identify and suggest improvements to slow or inefficient code

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