accelint-ts-performance

TypeScript Performance Optimization

Systematic performance optimization for JavaScript/TypeScript codebases. Combines audit workflow with expert-level optimization patterns for runtime performance.

NEVER Do When Optimizing Performance

Note: For general best practices (type safety with any/enum, avoiding null, not mutating parameters), use the accelint-ts-best-practices skill instead. This section focuses exclusively on performance-specific anti-patterns.

• NEVER assume code is cold path - Utility functions, formatters, parsers, and validators appear simple but are frequently called in loops, rendering pipelines, or real-time systems. Always audit ALL code for performance anti-patterns. Do not make assumptions about usage frequency or skip auditing based on perceived simplicity.

• NEVER apply all optimizations blindly - Performance patterns have trade-offs. Balance optimization gains against code complexity. When conducting audits, identify ALL anti-patterns through systematic analysis and report them with expected gains. Let users decide which optimizations to apply based on their specific context.

• NEVER ignore algorithmic complexity - Optimizing O(n²) code with micro-optimizations is futile. For n=1000, algorithmic fix (O(n² → O(n)) yields 1000x speedup; micro-optimizations yield 1.1-2x at best. Fix algorithm first: use Maps/Sets for O(1) lookups, eliminate nested iterations, choose appropriate data structures.

• NEVER sacrifice correctness for speed - Performance bugs are still bugs. Optimizations frequently break edge cases: off-by-one errors in manual loops, wrong behavior for empty arrays, null handling issues. Verify behavior matches before and after. Add comprehensive tests covering edge cases before optimizing—catching bugs in production costs far more than any performance gain.

• NEVER optimize code you don't own - Shared utilities, library internals, or code actively developed by others creates merge conflicts, duplicates effort, and confuses ownership. Performance changes affect all callers; coordinate with owners or defer optimization until code stabilizes.