# Check logs
tail -f logs/app.log | grep -i error

# Check recent changes
git log --oneline -20
git diff HEAD~5

# Check environment
node --version
npm list --depth=0

git bisect start
git bisect bad HEAD
git bisect good <known-good-commit>

// Strategic console logging
console.log('[DEBUG] Function entry:', { args, state });
console.trace('Call stack');
console.time('operation'); // ... console.timeEnd('operation');

// Debugger statement
debugger; // Pauses in DevTools

// Node.js debugging
// node --inspect-brk app.js

-- Check recent queries
EXPLAIN ANALYZE SELECT ...;

-- Check locks
SELECT * FROM pg_locks;

-- Check connections
SELECT * FROM pg_stat_activity;

describe('Bug fix: #123', () => {
  it('should handle the edge case that caused the bug', () => {
    // Arrange: Set up the exact conditions
    // Act: Trigger the bug scenario
    // Assert: Verify correct behavior
  });
});

fix: Brief description of the fix

Root cause: [Explain why the bug occurred]
Solution: [Explain what the fix does]

Fixes #123

// Add timeout to detect hanging promises
const withTimeout = (promise, ms) =>
  Promise.race([
    promise,
    new Promise((_, reject) =>
      setTimeout(() => reject(new Error('Timeout')), ms)
    )
  ]);

// Track state changes
const debugState = (label, state) => {
  console.log(`[${label}]`, JSON.stringify(state, null, 2));
  return state;
};

# Check if service is reachable
curl -v http://localhost:3000/health

# Check DNS
nslookup api.example.com

# Check ports
netstat -tlnp | grep 3000