Calculator Library

A comprehensive TypeScript calculator library built with Vite, featuring basic and advanced mathematical operations with configurable precision and error handling.

Features

• ✅ Basic arithmetic operations (add, subtract, multiply, divide)
• ✅ Configurable precision
• ✅ Flexible error handling
• ✅ Full TypeScript support
• ✅ Zero dependencies

TODO

• ✅ Advanced operations (power, square root, factorial, percentage)
• ✅ Expression evaluation
• ✅ Comprehensive test coverage

Installation

npm install @mrborek/calculator-lib

Usage

Using the Calculator Class

import Calculator from 'calculator-lib';

// Create a calculator instance
const calc = new Calculator();

// Basic operations
calc.add(2, 3);        // 5
calc.subtract(10, 4);  // 6
calc.multiply(3, 4);   // 12
calc.divide(15, 3);    // 5

// Advanced operations
calc.power(2, 3);      // 8
calc.sqrt(16);         // 4
calc.factorial(5);     // 120
calc.percentage(100, 10); // 10

// Expression evaluation
calc.calculate('2 + 3 * 4'); // 14
calc.calculate('(2 + 3) * 4'); // 20

Using Utility Functions

import { add, subtract, multiply, divide } from 'calculator-lib';

add(2, 3);        // 5
subtract(10, 4);  // 6
multiply(3, 4);   // 12
divide(15, 3);    // 5

Configuration Options

import Calculator from 'calculator-lib';

// Configure precision and error handling
const calc = new Calculator({
  precision: 2,        // Round results to 2 decimal places
  throwOnError: false  // Return NaN instead of throwing errors
});

calc.divide(1, 3);  // 0.33 (instead of 0.3333333333)
calc.divide(5, 0);  // NaN (instead of throwing CalculationError)

API Reference

Calculator Class

Constructor

new Calculator(options?: CalculatorOptions)

Options:

• precision?: number - Number of decimal places for results (default: 2)
• throwOnError?: boolean - Whether to throw errors or return NaN (default: true)

Methods

• add(a: number, b: number): number - Addition
• subtract(a: number, b: number): number - Subtraction
• multiply(a: number, b: number): number - Multiplication
• divide(a: number, b: number): number - Division
• power(base: number, exponent: number): number - Exponentiation
• sqrt(value: number): number - Square root
• percentage(value: number, percent: number): number - Percentage calculation
• factorial(n: number): number - Factorial (for non-negative integers)
• calculate(expression: string): number - Expression evaluation

Utility Functions

All calculator methods are also available as standalone functions:

import { add, subtract, multiply, divide, power, sqrt, percentage, factorial } from 'calculator-lib';

Error Handling

The library includes a custom CalculationError class for mathematical errors:

import Calculator, { CalculationError } from 'calculator-lib';

const calc = new Calculator();

try {
  calc.divide(5, 0);
} catch (error) {
  if (error instanceof CalculationError) {
    console.log('Mathematical error:', error.message);
  }
}

Development

Setup

# Clone the repository
git clone https://github.com/mrborek/calculator.git
cd calculator-lib

# Install dependencies
npm install

Scripts

# Development mode
npm run dev

# Build the library
npm run build

# Run tests
npm run test

# Run tests with coverage
npm run test:coverage

# Lint code
npm run lint

Building

The library is built using Vite and outputs:

• ES modules (dist/index.es.js)
• UMD bundle (dist/index.umd.js)
• TypeScript declarations (dist/index.d.ts)

Testing

The library includes comprehensive tests using Vitest:

npm run test

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Changelog

v0.0.1

• Initial release
• Basic arithmetic operations
• Configurable precision and error handling
• Full TypeScript support