fp-ts Option and Either

To handle nullable values safely in TypeScript, convert them to Option using fp-ts fromNullable. This wraps undefined values in a typed structure, allowing you to extract them safely using getOrElse and avoid runtime errors.

The best way to propagate typed errors in TypeScript is by using fp-ts Either. By returning right for success and left for failure, you can build robust validation flows that force explicit error handling at compile time.

To compose functional pipelines for error handling in TypeScript, use fp-ts pipe with map and chain. This allows you to sequence operations that might fail, passing Either or Option values through readable transformations.

Yes, fp-ts Option works with fromPredicate for input validation. You can use fromPredicate to check if a value meets specific criteria, automatically wrapping valid inputs in an Option and returning none if the condition fails.

You should use fold with fp-ts Either and Option when you need to extract a final value from a pipeline. Fold forces you to handle both the success and failure cases, ensuring safe unwrapping of the monadic value.