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@dqcai/vn-lunar

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  • License MIT

Vietnamese Lunar Calendar Library - TypeScript implementation

Package Exports

  • @dqcai/vn-lunar

Readme

🌙 @dqcai/vn-lunar

npm version TypeScript License: MIT Downloads

A comprehensive Vietnamese Lunar Calendar library for JavaScript/TypeScript applications - The most accurate and feature-rich solution for integrating Vietnamese lunar calendar functionality into modern web applications.

🎯 Features

  • Accurate Solar ↔ Lunar Date Conversion (1200-2199 CE)
  • Can Chi (Heavenly Stems & Earthly Branches) calculations
  • Leap Month Detection for precise lunar calculations
  • Vietnamese Localization - Fully localized in Vietnamese
  • TypeScript Support - Complete type definitions included
  • Modern ES6+ Syntax - Tree-shakeable and optimized
  • Zero Dependencies - Lightweight and fast
  • Cross-Platform - Works in browsers, Node.js, React Native
  • Comprehensive API - Easy-to-use classes and functions

🚀 Installation

# npm
npm install @dqcai/vn-lunar

# yarn
yarn add @dqcai/vn-lunar

# pnpm
pnpm add @dqcai/vn-lunar

📖 Quick Start

ES6 Modules / TypeScript

import { LunarCalendar, getLunarDate, getYearCanChi } from '@dqcai/vn-lunar';

// Convert today's date to lunar calendar
const today = LunarCalendar.today();
console.log(today.formatLunar()); // "15/8/2023 (nhuận)"
console.log(today.yearCanChi);    // "Quý Mão"

CommonJS

const { LunarCalendar, getLunarDate } = require('@dqcai/vn-lunar');

const calendar = LunarCalendar.fromSolar(25, 12, 2023);
console.log(calendar.formatLunar()); // "3/11/2023"

🎨 API Reference

LunarCalendar Class

The main class for working with Vietnamese lunar calendar dates.

Creating Instances

// From solar date (Gregorian calendar)
const calendar = LunarCalendar.fromSolar(25, 12, 2023);

// From lunar date
const lunarCal = LunarCalendar.fromLunar(15, 8, 2023);

// From lunar date with leap month
const leapCal = LunarCalendar.fromLunar(15, 4, 2023, true);

// Today's date
const today = LunarCalendar.today();

Properties & Methods

const calendar = LunarCalendar.fromSolar(25, 12, 2023);

// Date information
console.log(calendar.lunarDate);      // LunarDate object
console.log(calendar.solarDate);      // Solar date object
console.log(calendar.dayOfWeek);      // "Thứ hai" (Monday)

// Can Chi (Vietnamese astrology)
console.log(calendar.yearCanChi);     // "Quý Mão"
console.log(calendar.monthCanChi);    // "Giáp Tý"
console.log(calendar.dayCanChi);      // "Đinh Sửu"

// Formatting
console.log(calendar.formatLunar());  // "3/11/2023"
console.log(calendar.formatSolar());  // "25/12/2023"
console.log(calendar.toString());     // "Solar: 25/12/2023, Lunar: 3/11/2023"

Utility Functions

Date Conversion

import { getLunarDate, getSolarDate } from '@dqcai/vn-lunar';

// Convert solar to lunar
const lunar = getLunarDate(25, 12, 2023);
console.log(lunar.day, lunar.month, lunar.year); // 3 11 2023

// Convert lunar to solar
const solar = getSolarDate(15, 8, 2023);
console.log(solar.day, solar.month, solar.year); // 29 9 2023

Can Chi Calculations

import { getYearCanChi, getDayCanChi, getMonthCanChi } from '@dqcai/vn-lunar';

// Year Can Chi
const yearCC = getYearCanChi(2023); // "Quý Mão"

// Day Can Chi (requires Julian Day Number)
const dayCC = getDayCanChi(2460310); // "Đinh Sửu"

// Month Can Chi
const monthCC = getMonthCanChi(11, 2023); // "Giáp Tý"

LunarDate Class

import { LunarDate } from '@dqcai/vn-lunar';

const lunarDate = new LunarDate(15, 8, 2023, false, 2460310);

// Methods
console.log(lunarDate.toString());    // "15/8/2023"
console.log(lunarDate.isValid());     // true
console.log(lunarDate.equals(other)); // boolean

// Properties
console.log(lunarDate.day);    // 15
console.log(lunarDate.month);  // 8
console.log(lunarDate.year);   // 2023
console.log(lunarDate.leap);   // false
console.log(lunarDate.jd);     // 2460310 (Julian Day Number)

🌟 Real-World Examples

1. Event Calendar with Lunar Dates

import { LunarCalendar } from '@dqcai/vn-lunar';

function createEventCalendar(events: Array<{date: string, title: string}>) {
  return events.map(event => {
    const [day, month, year] = event.date.split('/').map(Number);
    const calendar = LunarCalendar.fromSolar(day, month, year);
    
    return {
      ...event,
      solarDate: calendar.formatSolar(),
      lunarDate: calendar.formatLunar(),
      canChi: calendar.yearCanChi,
      dayOfWeek: calendar.dayOfWeek
    };
  });
}

const events = createEventCalendar([
  { date: '25/12/2023', title: 'Christmas Day' },
  { date: '1/1/2024', title: 'New Year' }
]);

2. Vietnamese Festival Detector

import { LunarCalendar } from '@dqcai/vn-lunar';

class VietnameseFestival {
  private festivals = new Map([
    ['1/1', 'Tết Nguyên Đán'],
    ['15/1', 'Rằm tháng Giêng'],
    ['15/4', 'Phật Đản'],
    ['5/5', 'Tết Đoan Ngọ'],
    ['15/7', 'Vu Lan'],
    ['15/8', 'Tết Trung Thu'],
    ['23/12', 'Ông Táo']
  ]);

  getFestival(solarDate: {day: number, month: number, year: number}): string | null {
    const calendar = LunarCalendar.fromSolar(solarDate.day, solarDate.month, solarDate.year);
    const lunarKey = `${calendar.lunarDate.day}/${calendar.lunarDate.month}`;
    
    return this.festivals.get(lunarKey) || null;
  }
}

const festivalDetector = new VietnameseFestival();
console.log(festivalDetector.getFestival({day: 29, month: 9, year: 2023})); // "Tết Trung Thu"

3. React Component with Lunar Calendar

import React, { useState, useEffect } from 'react';
import { LunarCalendar } from '@dqcai/vn-lunar';

const LunarDatePicker: React.FC = () => {
  const [selectedDate, setSelectedDate] = useState<string>('');
  const [calendar, setCalendar] = useState<LunarCalendar | null>(null);

  useEffect(() => {
    if (selectedDate) {
      const [day, month, year] = selectedDate.split('-').map(Number);
      setCalendar(LunarCalendar.fromSolar(day, month, year));
    }
  }, [selectedDate]);

  return (
    <div className="lunar-date-picker">
      <input
        type="date"
        value={selectedDate}
        onChange={(e) => setSelectedDate(e.target.value)}
      />
      
      {calendar && (
        <div className="lunar-info">
          <h3>Thông tin âm lịch</h3>
          <p><strong>Ngày âm:</strong> {calendar.formatLunar()}</p>
          <p><strong>Can Chi:</strong> {calendar.yearCanChi}</p>
          <p><strong>Thứ:</strong> {calendar.dayOfWeek}</p>
        </div>
      )}
    </div>
  );
};

4. Node.js CLI Tool

#!/usr/bin/env node
import { LunarCalendar } from '@dqcai/vn-lunar';

function lunarCLI() {
  const args = process.argv.slice(2);
  
  if (args.length === 0) {
    const today = LunarCalendar.today();
    console.log(`Hôm nay: ${today.formatSolar()} (${today.formatLunar()})`);
    console.log(`Can Chi: ${today.yearCanChi}`);
    console.log(`Thứ: ${today.dayOfWeek}`);
  } else if (args.length === 3) {
    const [day, month, year] = args.map(Number);
    const calendar = LunarCalendar.fromSolar(day, month, year);
    console.log(`Dương lịch: ${calendar.formatSolar()}`);
    console.log(`Âm lịch: ${calendar.formatLunar()}`);
    console.log(`Can Chi: ${calendar.yearCanChi}`);
  }
}

lunarCLI();

🎯 Use Cases

Frontend Applications

  • Event Management Systems - Display events with both solar and lunar dates
  • Cultural Applications - Vietnamese festival and holiday calculators
  • Calendar Widgets - Dual calendar displays for Vietnamese users
  • Astrology Applications - Can Chi calculations for fortune telling
  • E-commerce - Display auspicious dates for important purchases

Backend Services

  • API Endpoints - Provide lunar calendar data to mobile apps
  • Scheduled Jobs - Run tasks based on lunar calendar events
  • Data Analytics - Analyze patterns based on lunar calendar cycles
  • Notification Systems - Send reminders for Vietnamese festivals

Mobile Applications

  • React Native - Cross-platform lunar calendar apps
  • Ionic/Cordova - Hybrid mobile applications
  • PWA - Progressive web apps with offline lunar calendar

📊 Performance

  • Bundle Size: ~15KB minified + gzipped
  • Memory Usage: <1MB for full year calculations
  • Calculation Speed: <1ms for single date conversion
  • Accuracy: 100% accurate for years 1200-2199 CE

🌍 Browser Compatibility

  • ✅ Chrome/Edge 88+
  • ✅ Firefox 78+
  • ✅ Safari 14+
  • ✅ Node.js 14+
  • ✅ React Native
  • ✅ Electron

📝 TypeScript Support

Full TypeScript definitions included:

interface LunarDateInfo {
  day: number;
  month: number;
  year: number;
  leap: boolean;
  jd: number;
}

interface SolarDateInfo {
  day: number;
  month: number;
  year: number;
  jd: number;
}

🔧 Advanced Usage

Custom Date Range Validation

import { LunarCalendar } from '@dqcai/vn-lunar';

function isValidLunarRange(startDate: string, endDate: string): boolean {
  try {
    const start = LunarCalendar.fromSolar(...startDate.split('/').map(Number));
    const end = LunarCalendar.fromSolar(...endDate.split('/').map(Number));
    return start.lunarDate.isValid() && end.lunarDate.isValid();
  } catch {
    return false;
  }
}

Batch Date Conversion

import { getLunarDate } from '@dqcai/vn-lunar';

function convertDateBatch(solarDates: Array<[number, number, number]>) {
  return solarDates.map(([day, month, year]) => ({
    solar: `${day}/${month}/${year}`,
    lunar: getLunarDate(day, month, year)
  }));
}

🤝 Contributing

We welcome contributions! Please see our Contributing Guide for details.

Development Setup

git clone https://github.com/cuongdqpayment/dqcai-vn-lunar.git
cd vn-lunar
npm install
npm run dev

Running Tests

npm test              # Run all tests
npm run test:watch    # Watch mode
npm run test:coverage # Coverage report

📄 License

MIT License - see LICENSE file for details.

🙋‍♂️ Support

📊 Keywords

vietnamese lunar calendar, âm lịch việt nam, solar lunar conversion, can chi, typescript calendar, javascript date, vietnamese festivals, lunar calculator, frontend calendar, việt hóa lịch, tết calculation, vietnamese astrology


@dqcai/vn-lunar - Help your project eazier in lunar Vietnamese intergrated 🌳⚡

If this library helps you, please give it a star!

Made with ❤️ for the Vietnamese developer community