TypeScript Isolated Declarations: Real-World Performance Gains in Monorepo Build Times Most monorepo build bottlenecks stem from sequential declaration file generation. TypeScript's default behavior requires analyzing every import chain before emitting a single .d.ts file. This sequential dependency creates a cascading delay where package builds queue behind one another. The --isolatedDeclarations flag eliminates this bottleneck by enabling parallel declaration emit. Teams report 3x to 1...