Majik Money

Majik Money lightweight JavaScript/TypeScript library for precise money and currency modeling, engineered to eliminate floating-point errors inherent in JavaScript. It’s perfect for scenarios where you need financial calculations, currency conversions, accounting operations, or money-based simulations with exact results.

✨ Features

• Represent money and currencies with full decimal precision using decimal.js.
• Perform arithmetic operations (add, subtract, multiply, divide) without floating-point errors.
• Convert between minor and major currency units automatically.
• Support for currency conversion between multiple defined currencies.
• Chainable API for fluent money operations.
• Serialize/deserialize money objects with toJSON() and parseFromJSON().
• Fully TypeScript-friendly with strict type safety.
• Works in Node.js and browser environments.

Why Majik Money is More Than decimal.js

decimal.js gives you arbitrary-precision arithmetic, but Majik Money adds a full financial and currency layer, designed for real-world applications:

Currency & Unit Awareness

• Each instance is tied to an ISO 4217 currency (USD, PHP, etc.), including minor unit handling (cents, centavos).
• Automatic conversion between major units (dollars/pesos) and minor units (cents/centavos) with correct rounding.

Immutable, Chainable Operations

• All operations (add, subtract, multiply, etc.) return new MajikMoney instances, preventing accidental mutations.
• Chainable API enables concise, readable financial calculations.

Allocation & Splitting

• Split amounts evenly or according to custom ratios, with remainders handled correctly.
• Perfect for payroll, expense sharing, or dividing investments.

Percentage & Compound Calculations

• Built-in methods for applying, adding, or subtracting percentages, e.g., taxes, discounts, or interest.
• Compound growth calculations as MajikMoney objects, preserving precision and rounding rules.

Serialization & Safe JSON

• Includes currency info and type hints for safe storage and transport.
• Recursive helpers (serializeMoney / deserializeMoney) make working with nested objects seamless.

Statistical Helpers

• Array-level calculations like sum, average, weighted average, median, variance, and standard deviation with currency safety.

Currency Conversion & FX Support

• Convert between currencies with explicit rates or quoted FX rates.
• Avoids errors from manual conversions.

Human-Friendly Formatting

Localized currency formatting (₱1,234.56) ready for display.

Domain-Specific Utilities

• Inverted division (invertDivide) for financial ratios.
• Designed specifically for money modeling, not just numbers.

In short: decimal.js handles numbers. Majik Money handles real money — safely, accurately, and with all the financial logic your applications need.

Full API Docs

📦 Installation

npm i @thezelijah/majik-money

Usage

Create a Money Instance

import { MajikMoney, CURRENCIES } from "@thezelijah/majik-money";

// From major units (human-readable, e.g., dollars/pesos)
const majorAmount = MajikMoney.fromMajor(1234.56, "PHP");

// From minor units (integer, e.g., centavos)
const minorAmount = MajikMoney.fromMinor(123456, "PHP");

// Default zero with currency
const zeroAmount = MajikMoney.zero("PHP")
// Use CURRENCIES from /currency.ts

console.log(majorAmount.format()); // "₱1,234.56"
console.log(minorAmount.format()); // "₱1,234.56"
console.log(zeroAmount.format()); // "₱0.00"
;   

Arithmetic Operations (Immutable)

const a = MajikMoney.fromMajor(100, "USD");
const b = MajikMoney.fromMajor(50, "USD");

const sum = a.add(b);               // 150 USD
const difference = a.subtract(b);   // 50 USD
const product = a.multiply(3);      // 300 USD
const quotient = a.divide(4);       // 25 USD

console.log(sum.toString(), difference.toString(), product.toString(), quotient.toString());

Percentage Operations

Array of periods with interest, principal, total, and tax.

const price = MajikMoney.fromMajor(200, "PHP");

const tax = price.applyPercentage(0.12);       // 12% of 200
const priceWithTax = price.addPercentage(0.12);
const priceAfterDiscount = price.subtractPercentage(0.1); // 10% discount

Compound Growth

const principal = MajikMoney.fromMajor(1000, "USD");
const futureValue = principal.compound(0.05, 3); // 5% per period for 3 periods
console.log(futureValue.format()); // "₱1,157.63" (example)

Allocation / Splitting

const total = MajikMoney.fromMajor(1000, "PHP");

// Even split
const parts = total.evenSplit(3);
parts.forEach(p => console.log(p.format())); // [₱333.34, ₱333.33, ₱333.33]

// Custom allocation ratios
const allocated = total.allocate([1, 2, 3]);
allocated.forEach(p => console.log(p.format())); // e.g., ₱166.67, ₱333.33, ₱500.00

Currency Conversion

const usd = MajikMoney.fromMajor(100, "USD");
const php = usd.convert(56.75, CURRENCIES["PHP"]);
console.log(php.format()); // "₱5,675.00"

// Using quoted FX rate
const php2 = usd.convertFromQuoted(0.01763, CURRENCIES["PHP"]);
console.log(php2.format());

Comparison & Utility Methods

const x = MajikMoney.fromMajor(100, "USD");
const y = MajikMoney.fromMajor(50, "USD");

console.log(x.equals(y));       // false
console.log(x.greaterThan(y));  // true
console.log(x.isPositive());    // true
console.log(x.negate().isNegative()); // true

Ratios & Inverted Operations

const x = MajikMoney.fromMajor(200, "PHP");
console.log(x.ratio(MajikMoney.fromMajor(50, "PHP"))); // 4

const inverted = x.invertDivide(2); // 2 ÷ 200 PHP
console.log(inverted.toMajor()); // 0.01 PHP

Serialization & Deserialization

const money = MajikMoney.fromMajor(1234.56, "PHP");
const json = money.toJSON();
console.log(json); // { amount: "123456", currency: "PHP", __type: "MajikMoney" }

const parsed = MajikMoney.parseFromJSON(json);
console.log(parsed.format()); // "₱1,234.56"

// Recursive helpers for complex objects
const serialized = serializeMoney({ payment: money });
const deserialized = deserializeMoney(serialized);
console.log(deserialized.payment.format()); // "₱1,234.56"

Statistical Helpers (Static Methods)

const arr = [
  MajikMoney.fromMajor(100, "USD"),
  MajikMoney.fromMajor(200, "USD"),
  MajikMoney.fromMajor(300, "USD")
];

console.log(MajikMoney.sum(arr).format());          // 600 USD
console.log(MajikMoney.average(arr).format());      // 200 USD
console.log(MajikMoney.weightedAverage(arr, [1,2,3]).format()); // 233.33 USD
console.log(MajikMoney.median(arr).format());       // 200 USD
console.log(MajikMoney.min(arr).format());          // 100 USD
console.log(MajikMoney.max(arr).format());          // 300 USD
console.log(MajikMoney.standardDeviation(arr).toMajor()); // ~81.65 USD

Use Cases

• Accounting and ledger operations with exact arithmetic.
• Currency conversion for fintech or e-commerce apps.
• Budgeting and expense tracking with precise calculations.
• Financial dashboards or calculators.
• Simulations for investments or payments over time.

Best Practices

• Always use MajikMoney objects instead of raw numbers for calculations.
• Avoid mixing currencies without explicit conversion rates.
• Serialize with toJSON() for storage and communication.
• Use chainable operations for concise and readable code.
• Prefer toMajor() for display to users, and toMinor() for storage or calculations.

Contributing

Contributions, bug reports, and suggestions are welcome! Feel free to fork and open a pull request.

License

ISC — free for personal and commercial use.

Author

Made with 💙 by @thezelijah

About the Developer

• Developer: Josef Elijah Fabian
• GitHub: https://github.com/jedlsf
• Project Repository: https://github.com/jedlsf/majik-money

Contact

• Business Email: [email protected]
• Official Website: https://www.thezelijah.world