effect-ts

Dependency injection in TypeScript uses Layers and Context to build modular, testable services. Layers allow you to compose services and manage their lifecycles, making it easier to isolate dependencies and mock them during testing without altering core business logic.

Fiber-based concurrency patterns implement high-performance parallel tasks in functional TypeScript. Fibers provide lightweight, cooperative multitasking primitives that enable you to run concurrent operations safely and manage their cancellation or interruption robustly.

Refactoring a legacy service to use Effect involves designing a proper Layer composition and replacing untyped errors with a robust, domain-specific error hierarchy. This transition ensures production-ready service composition and eliminates common side-effect anti-patterns.

Functional TypeScript with Effect supports data streams and resource management through Stream primitives. Streams enable high-performance processing of asynchronous data pipelines, while built-in resource management ensures safe acquisition and release of external resources.

Typed errors prevent common anti-patterns by ensuring type-safe failure recovery, unlike untyped exceptions. By using tagged errors and unions, you explicitly define potential failure states in the function signature, forcing the compiler to verify that all error cases are handled.