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Show HN: FP-pack – Functional pipelines in TypeScript without monads

Hi HN,

I built fp-pack, a small TypeScript functional utility library focused on pipe-first composition.

The goal is to keep pipelines simple and readable, while still supporting early exits and side effects — without introducing monads like Option or Either.

Most code uses plain pipe/pipeAsync. For the few cases that need early termination, fp-pack provides a SideEffect-based pipeline that short-circuits safely.

I also wrote an “AI agent skills” document to help LLMs generate consistent fp-pack-style code.

Feedback, criticism, or questions are very welcome.

How is this not a monad? It might be trying really hard not to reify the core concept of a monad, but it seems to me like it ends up being essentially a complicated monad.

5 days agoby epgui

One thing I’d especially like feedback on is the SideEffect approach.

It’s intentionally not a monad, and I’m curious how others feel about this trade-off compared to Option/Either in real-world TypeScript codebases.

5 days agoby superlucky84

While I like the concept, the side-effect pattern might be difficult for the average developer to understand (without fp-pack knowledge) in a shared codebase:

https://github.com/superlucky84/fp-pack?tab=readme-ov-file#s...

Still, this approach is very useful for most business logic, too bad most programming languages don't provide a nice syntax for this.

5 days agoby eterps

The default any return type from pipelines is kind of brutal. Seems like a real footgun. Is that fixable?

5 days agoby wk_end

Every time I introduce something like this teams complain. RX is a brain antipattern

5 days agoby almosthere

Haskell does not have nulls. Java 8 introduced Options, and now there are nulls and Options.

Please tell me you didn't just add SideEffects to a language full of side-effects.

5 days agoby mrkeen