@factorn/money

Class-first money utilities for Node.js and the browser, built on Dinero.js v2.

Install

pnpm add @factorn/money
# or: npm install @factorn/money

Choose a calculator

| Import | Amount type | Use when | | ----------------------- | ----------- | ------------------------------------ | | @factorn/money | number | Typical retail / app amounts | | @factorn/money/bigint | bigint | Large ledgers, high-precision totals |

Both entries expose the same Money API.

import { Money, USD, EUR } from "@factorn/money";

const price = Money.fromMinor(1999, USD); // $19.99
const tax = price.percentage(15);
const total = Money.sum([price, tax]);

price.format("en-US"); // "$19.99"
JSON.stringify(price); // {"amount":1999,"currency":"USD","scale":2}

import { Money, USD } from "@factorn/money/bigint";

const price = Money.fromMinor(1999n, USD);
JSON.stringify(price); // {"amount":"1999","currency":"USD","scale":2}

Common operations

import { Money, USD, EUR, halfEven } from "@factorn/money";

const a = Money.fromMajor("10.00", USD);
const b = Money.fromMajor(2.5, USD);

a.add(b);
a.subtract(b);
a.multiply(3);
a.multiply({ amount: 21, scale: 1 }); // × 2.1
a.allocate([1, 2]);
a.percentage(15); // integer percent
a.percentage("12.5"); // fractional percent as string
a.convert(EUR, { EUR: { amount: 89, scale: 2 } });
a.transformScale(3, halfEven);
a.trimScale();

Scripts

| Command | Description | | ---------------- | ----------------- | | pnpm build | Build with tsdown | | pnpm typecheck | Type-check | | pnpm test | Run tests | | pnpm lint | Lint with oxlint | | pnpm format | Format with oxfmt |