Typescript

This is a compilation-focused performance guide with 45 rules split across type system optimization, compiler config, and async patterns. It's most useful when you're dealing with slow tsc builds or need to configure tsconfig.json properly. The categorization by priority (type system and compiler settings marked CRITICAL, async and modules HIGH) makes it easy to know what actually matters. What stands out is the specificity: exact impact metrics like "30-50% faster declaration emit" for explicit return types or "50-90% faster rebuilds" for incremental compilation. If you're hunting down why your TypeScript build is slow or trying to prevent common footguns like barrel imports or deeply nested generics, this gives you concrete rules with measurable outcomes rather than vague best practices.