🌘 SolarLunar

Professional Solar-Lunar Calendar Conversion Library

High-performance solar-lunar calendar conversion with天干地支, 生肖, and 24 solar terms support

🚀 Features

• ** blazing Fast**: >340,000 conversions per second
• Accurate: Precise calculations for 1900-2100 period
• Complete: Full support for 天干地支, 生肖, and 24 solar terms
• Modern: ESM, CJS, and UMD module support
• Typed: Full TypeScript support
• Lightweight: Zero dependencies
• Reliable: 100% test coverage

📦 Installation

npm install solarlunar

Note: Use lowercase solarlunar (not solarLunar) when importing. Some case-sensitive file systems may fail to resolve the package with uppercase letters.

🛠️ Quick Start

ES6 Modules

import solarLunar from 'solarlunar';

// Solar to Lunar
const lunar = solarLunar.solar2lunar(2023, 10, 15);
console.log(lunar.lYear, lunar.lMonth, lunar.lDay); // 2023 8 30

// Lunar to Solar
const solar = solarLunar.lunar2solar(2023, 8, 30);
console.log(solar.cYear, solar.cMonth, solar.cDay); // 2023 10 15

CommonJS

const solarLunar = require('solarlunar');

Browser

<script src="https://unpkg.com/solarlunar/dist/solarlunar.min.js"></script>
<script>
  const result = solarLunar.solar2lunar(2023, 10, 15);
</script>

📋 API Reference

solarLunar.solar2lunar(year, month, day)

Convert solar date to lunar date.

Parameters:

• year (Number): Solar year (1900-2100)
• month (Number): Solar month (1-12)
• day (Number): Solar day (1-31)

Returns: Object with lunar date information

solarLunar.lunar2solar(year, month, day, isLeapMonth?)

Convert lunar date to solar date.

Parameters:

• year (Number): Lunar year (1900-2100)
• month (Number): Lunar month (1-12)
• day (Number): Lunar day (1-30)
• isLeapMonth (Boolean, optional): Whether it's a leap month

Returns: Object with solar date information

🎯 Returned Object Structure

{
  // Basic lunar info
  lYear: 2023,              // Lunar year
  lMonth: 8,                // Lunar month
  lDay: 30,                 // Lunar day
  isLeap: false,            // Whether leap month

  // Basic solar info
  cYear: 2023,              // Solar year
  cMonth: 10,               // Solar month
  cDay: 15,                 // Solar day
  isToday: false,           // Whether today

  // Chinese representations
  yearCn: '二零二三年',       // Chinese year
  monthCn: '八月',           // Chinese month
  dayCn: '三十',             // Chinese day
  ncWeek: '星期日',           // Chinese weekday

  // Stems and Branches
  gzYear: '癸卯',            // Year stem-branch
  gzMonth: '辛酉',           // Month stem-branch
  gzDay: '甲子',             // Day stem-branch

  // Zodiac and terms
  animal: '兔',              // Zodiac animal
  isTerm: false,             // Whether solar term day
  term: '',                  // Solar term name if applicable

  // Weekday info
  nWeek: 7                   // Weekday number (1-7 for Mon-Sun)
}

🧪 Examples

Complete Conversion

const result = solarLunar.solar2lunar(2023, 12, 22); // Winter Solstice day

console.log(result);
/*
{
  lYear: 2023, lMonth: 11, lDay: 10,
  yearCn: '二零二三年', monthCn: '冬月', dayCn: '初十',
  gzYear: '癸卯', gzMonth: '癸丑', gzDay: '甲戌',
  animal: '兔',
  isTerm: true, term: '冬至',
  cYear: 2023, cMonth: 12, cDay: 22,
  isToday: false, isLeap: false,
  nWeek: 5, ncWeek: '星期五'
}
*/

Zodiac Calculation

// Precise zodiac based on Spring Festival
const animal = solarLunar.getAnimal(2023, 2, 5); // Accurate based on 立春

Solar Term Detection

const hasTerm = solarLunar.solar2lunar(2023, 12, 22);
if (hasTerm.isTerm) {
  console.log(`Today is ${hasTerm.term} solar term!`);
}

🏗️ Architecture

Modern Build System

• Rollup 4: Optimized builds with tree-shaking
• Vitest: Fast, modern testing framework
• ESLint + Prettier: Code quality and formatting
• TypeScript: Complete type definitions

Performance Optimizations

• Optimized algorithms for date calculations
• Precomputed data structures
• Efficient memory usage
• Fast lookup mechanisms

📊 Performance

| Operation | Average Time | Throughput | | ------------------ | ------------ | ------------------- | | Solar to Lunar | < 0.003ms | >340,000 ops/sec | | Lunar to Solar | < 0.004ms | >270,000 ops/sec | | Zodiac Calculation | < 0.001ms | >41,000,000 ops/sec |

🛡️ Reliability

• 57 Test Cases: 100% pass rate
• 1900-2100 Support: Full century range coverage
• Boundary Testing: Extensive edge case validation
• Security Audited: Clean dependency tree

📚 Documentation

• Quick Start Guide
• API Documentation
• Usage Examples
• Development Guide
• Release Notes

🤝 Contributing

We welcome contributions! Please see our Development Guide for how to get started.

Development Commands

npm install              # Install dependencies
npm test                # Run tests
npm run test:watch      # Watch mode for tests
npm run dev             # Development build watch
npm run build           # Production build
npm run lint            # Code quality check
npm run format          # Code formatting
npm run perf            # Performance benchmark
npm run typecheck       # Type checking
npm run security        # Security audit

📄 License

ISC License - Free and open source.

🙏 Acknowledgments

Based on the original work by JJonline, modernized and enhanced for contemporary JavaScript environments.

Made with ❤️ for the JavaScript Community

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