TypeScript Performance

Compilation Performance

• Incremental Compilation: incremental: true — TypeScript caches build info in .tsbuildinfo. Subsequent builds only recheck changed files. 2-10x faster rebuilds
• Project References: Split large codebase into packages — each compiles independently. Parallel builds with tsc --build. Only rebuild changed packages
• Type Complexity: Avoid deeply recursive conditional types — TypeScript has recursion limits. Simplify complex mapped types. Use type aliases to cache intermediate types
• Interface vs Type: interface is faster to check (implements caching). Use interface for object shapes. type for unions, intersections, and complex operations. Don't obsess — the difference is marginal for most projects
• skipLibCheck: true: Skip type checking of node_modules .d.ts files — significantly faster builds. Safe for most projects. Disable only when debugging type issues with libraries
• Bundler Performance: Use SWC (Rust-based) or esbuild instead of TSC for transpilation — 10-50x faster. Use TSC only for type checking (tsc --noEmit). Vite uses esbuild in dev, Rollup for production