Performance Optimization Skill

When analyzing code for performance, follow this structured process:

1. Understand What's Slow

• Ask or determine: what operation is slow? (page load, API response, build time, query, render)
• What's the current performance? (response time, load time, memory usage)
• What's the expected/acceptable performance?
• How much data is involved? (10 rows vs 10 million rows changes everything)

2. Algorithm & Data Structure Analysis

• Identify time complexity of key operations (O(n), O(n²), O(n log n), etc.)
• Look for nested loops over large datasets
• Check if a different data structure would help:
  • Array lookups that should be Map/Set/Object for O(1) access
  • Linear searches that should use binary search or indexing
  • Repeated array filtering that should be pre-grouped
• Look for unnecessary sorting or repeated work