fp-refactor

Refactoring imperative TypeScript to fp-ts involves replacing control flow with constructs like Either and TaskEither. You change return types, remove exceptions, and update call sites for a structured, testable migration.

Migrating error handling to fp-ts means replacing exceptions with Either or TaskEither types. This allows errors to be handled as values in the data flow, improving composability and testability across real-world modules.

TaskEither enables asynchronous composition by wrapping operations that can fail into a single type. You replace imperative async/await and try-catch blocks with TaskEither chains to handle side effects and errors functionally.

Yes, you can gradually refactor a legacy TypeScript project to functional programming by migrating small modules to fp-ts patterns with minimal disruption. This step-by-step approach allows identifying errors and updating types incrementally.

The Reader pattern in fp-ts is used when you need to pass dependencies through your functions explicitly. It replaces imperative dependency injection or global state, making data flow composable and testable during migration.