Money Money Money

This is a pre-release version. Use at your own risk.

A JavaScript library for dealing with money, safely.

Installation

npm install money-money-money

Basic usage

const { Money } = require('money-money-money');
const money = new Money('100', 'EUR');
console.log(money.toLocaleString());

Why another money library?

Have you ever tried to repesent the US national debt in Iranian rial?

27067291392010 USD * 42105 IRR / USD = 1139668304060581050 IRR

Many libraries would completely fail or silently lose accuracy. Not this one.

const { Money } = require('money-money-money');
const usNationalDebtUsd = new Money('27067291392010', 'USD');
const usNationalDebtIrr = usNationalDebtUsd.convertCurrency('IRR', '42105');
console.assert('1139668304060581050' === usNationalDebtIrr.toDecimalString());
console.assert('IRR' === usNationalDebtIrr.currency);

Truth in advertising

You cannot format IRR 1139668304060581050 precisely using the built-in toLocaleString function because it relies on Intl.NumberFormat.format which itself can only format a floating point Number.

const { Money } = require('money-money-money');
const money = new Money('1139668304060581050', 'IRR');
money.toLocaleString(); // throws Error

If you are fine with the loss of accuracy then you can call toLocaleString with the custom option precisionHandling.

const { Money } = require('money-money-money');
const money = new Money('1139668304060581050', 'IRR');
console.assert('IRR\u00A01,139,668,304,060,581,000' === money.toLocaleString(undefined, { precisionHandling: 'unchecked' }));
console.assert('~\u00A0IRR\u00A01,139,668,304,060,581,000' === money.toLocaleString(undefined, { precisionHandling: 'show_imprecision' }));

Dependencies

This library depends on big.js for arbitrary-precision decimal arithmetic.

Additionally the environment must provide Intl.NumberFormat. It is used to determine how many decimal places the currency uses and for formatting. Intl.NumberFormat is supported by all major browsers and all recent Node.js versions.

Please note: By default, Node.js versions 12 and earlier are built with small-icu. This means that formatting may be unavailable for your locale. For more information see the Node.js Internationalization Support. Since Node version 13 the full-icu is included by default.

License

This library is licensed under the MIT license.