Zestlet FP

A modern TypeScript functional programming utility library built with AI assistance, focusing on precise type inference and currying support.

This is currently in testing and subject to change, please proceed with caution.

AI-Assisted Development Approach

This library is built using an AI-assisted development method:

• Core functions and type definitions generated with AI assistance
• Manual review and optimization of critical components
• Comprehensive test suite to ensure code quality
• Type system designed by AI and validated by humans

Features

• Development Stage: Current version is being continuously improved, API may change
• Type Safety: Complete TypeScript support with precise type inference
• Pure Functions: Immutable operations with no side effects
• Curried Design: All functions support currying for partial application
• Point-Free Friendly: Optimized for functional composition patterns
• Modern TypeScript: Leverages latest TS features including const generics
• Lightweight: Focused API with no external dependencies

Installation

npm install @zestlet/fp
# or
yarn add @zestlet/fp
# or
pnpm add @zestlet/fp

Usage Example

import { filter, map, path, flow, pluck, prop, sortBy } from '@zestlet/fp';

const getNamesByCompose = map(prop('name'));
// const getNamesByCompose: <T, K2 extends keyof T & "name">(array: ArrayContainer<T>) => T[K2][]

const getNames = pluck('name');
// const getNames: <T2 extends Record<PropertyKey, unknown>>(array: readonly T2[]) => T2["name"][]

const example = [
  { name: 'Alice', age: 18 },
  { name: 'Bob', age: 20 },
] as const;

const names = getNames(example);
// const names: ("Alice" | "Bob")[]

const namesByCompose = getNamesByCompose(example);
// const namesByCompose: ("Alice" | "Bob")[]

// Getting all valid order customer names, sorted by name
const getSortedCustomerNames = flow(
  filter(path(['status', 'isValid'])),
  map(path(['customer', 'name'])),
  sortBy((a: string) => a.toLowerCase())
);

const orders = [
  { id: 1, customer: { name: 'Dave', id: 101 }, status: { isValid: true } },
  { id: 2, customer: { name: 'Alice', id: 102 }, status: { isValid: true } },
  { id: 3, customer: { name: 'Bob', id: 103 }, status: { isValid: false } },
] as const;

const customerNames = getSortedCustomerNames(orders);
// const customerNames: string[]

console.log(customerNames); // [ "Alice", "Dave" ]

License

MIT

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.