@acausal/distributions

Weighted random selection from discrete distributions — type-safe, serializable, with immutable and mutable APIs.

Install

npm install @acausal/distributions

Usage

import { Distribution } from '@acausal/distributions';

// Create from source weights
const loot = Distribution.new({ gold: 60, silver: 30, diamond: 10 });

// Pick one
Distribution.pickOne(loot);  // 'gold' (60% chance)

// Pick with mask (exclude items)
Distribution.pickOne(loot, ['gold']);  // 'silver' or 'diamond'

// Modify immutably
const boosted = Distribution.addNormalValues(loot, { diamond: 0.1 });

// Immutable class variant
const dist = new Distribution({ source: { a: 3, b: 1 }, seed: 42 });
const frozen = dist.clone(true);  // strip source, keep normalized

Supports blending, masking, source/normal weight separation, and full serialization. Built on @acausal/random.

Part of the acausal procedural generation toolkit.