@sylphx/pura

Pure FP for TypeScript - Fast, Type-Safe, Zero Compromise

Persistent data structures (HAMT, RRB-Tree) that make immutability faster than mutation.

Features

• 🚀 Faster than mutation - Structural sharing beats copying
• 🔒 Type-safe - Full TypeScript support with inference
• 🎯 Immer-like API - Familiar produce() interface
• 📦 Zero dependencies - Lightweight and fast
• 🌳 Persistent data structures - HAMT maps and RRB-Tree arrays

Installation

npm install @sylphx/pura

Quick Start

import { produce } from '@sylphx/pura'

// Immer-like produce API
const state = { count: 0, items: [1, 2, 3] }

const next = produce(state, draft => {
  draft.count++
  draft.items.push(4)
})

console.log(state.count) // 0 (unchanged)
console.log(next.count)  // 1 (new state)

Core APIs

produce(base, recipe)

Create new state by mutating a draft. Works like Immer.

const user = { name: 'Alice', age: 30 }
const updated = produce(user, draft => {
  draft.age = 31
})

pura(value) / unpura(value)

Convert between plain objects and persistent structures for maximum performance.

import { pura, unpura, produce } from '@sylphx/pura'

// Wrap data for persistent operations
const wrapped = pura({ items: [1, 2, 3] })

// Fast updates on persistent structures
const updated = produce(wrapped, draft => {
  draft.items.push(4)
})

// Unwrap back to plain objects when needed
const plain = unpura(updated)

Performance

Pura uses advanced persistent data structures (HAMT for objects/maps, RRB-Tree for arrays) that share structure between versions. This makes immutable updates faster than copying, especially for large datasets.

Adaptive strategies: Small collections use native objects/arrays. Large collections automatically upgrade to persistent structures. Best of both worlds.

Documentation

Full documentation available at pura.sylphx.com

• Getting Started
• API Reference
• Performance Guide
• Migration from Immer

License

MIT © SylphX Ltd

Links

• Documentation
• GitHub
• Issues
• npm