Optimize TypeScript Builds

Make TypeScript cheaper to type-check, build, or run without changing emitted behavior or the declared types. TypeScript cost has two separate sources: the compiler's work (checker, program size, declaration emit) and the JavaScript that TypeScript constructs and target produce. Each change applies one reference card to a cost that a counter, trace, emitted-code diff, or runtime profile attributes, is proven equivalent by an oracle, and is kept only if the metric the card names improves. Engine-level JavaScript tuning (object shapes, array kinds) belongs to the optimize-javascript-code skill.

Workflow