🧠 holo-fn

A minimal functional library for TypeScript featuring monads like Maybe, Either and Result. Built for composability and Rambda compatibility.

💡 Designed to work seamlessly with pipe from Rambda. Fully typed, immutable, and safe by default.

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✨ Features

• ✅ Functional types: Maybe, Either, Result
• 🛠️ Helpers: tap, inspect for debugging
• ⚙️ Pipe-friendly (Rambda/Ramda compatible)
• 🔒 Immutable by default
• 🧪 100% test coverage
• ⚡️ Zero dependencies
• 🧠 Full TypeScript inference

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🚀 Installation

npm install holo-fn

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📦 API Overview

API documentation can be found here

🧠 Examples

Safe object access

import { fromNullable, match } from 'holo-fn/maybe';

const double = (n: number) => n * 2;

const result = pipe(
  [5, 5, 6],
  (ns) => fromNullable(head(ns)),
  (x) => x.map(double),
  match({
    just: (n) => n,
    nothing: () => -1
  })
);

console.log(result); // 10

Optional parsing

import { fromNullable } from 'holo-fn/maybe';

const parsePrice = (input: string) =>
  fromNullable(parseFloat(input))
    .map(n => (n > 0 ? n : null))
    .chain(fromNullable)
    .unwrapOr(0)

console.log(parsePrice('123.45')) // 123.45
console.log(parsePrice('0')) // 0
console.log(parsePrice('-123.45')) // 0
console.log(parsePrice('abc')) // 0

Debug pipelines with tap

import { tap } from 'holo-fn';
import { just, map } from 'holo-fn/maybe';

const result = pipe(
  just(10),
  tap(x => console.log('Initial:', x.unwrapOr(0))),
  map(x => x * 2),
  tap(x => console.log('After double:', x.unwrapOr(0))),
  map(x => x + 5)
);
// Logs: "Initial: 10"
// Logs: "After double: 20"
// Returns: Just(25)

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Changelog

All notable changes to this project will be documented in here.

🤝 Contributing

Please refer to CONTRIBUTING.md for instructions on how to run tests, build the library, and contribute.

📜 License

Here license MIT