Function gregorianToLunar

Low-level pure functions for calendar conversion. Most users should prefer the ChineseDate value object API. These functions are useful when you need fine-grained control or want to build custom logic on top of the core algorithms.

gregorianToLunar(
    config: CalendarConfig,
    year: number,
    month: number,
    day: number,
): LunarDateValue
Convert Gregorian date to lunar date

This is the primary conversion function. It computes the JDE of the given Gregorian date, then determines the corresponding lunar date by finding the enclosing new moon and major solar term.

For dates in January before the 20th, the Gregorian year is adjusted backward because Chinese New Year never starts before January 20.
Parameters
- config: CalendarConfig
  Calendar configuration (determines epoch and timezone)
- year: number
  Gregorian year (e.g., 2024)
- month: number
  Month (1-12)
- day: number
  Day of month
Returns LunarDateValue
Lunar date value with cycle/year/month/leap/day
Example
```
gregorianToLunar(CHINESE_CONFIG, 2024, 6, 21)
// { cycle: 78, year: 34, month: 5, leap: false, day: 6 }

// Using Japanese calendar (different timezone may yield different results)
gregorianToLunar(JAPANESE_CONFIG, 2024, 6, 21)
// { cycle: 78, year: 34, month: 5, leap: false, day: 6 }
```
- Defined in core/algorithm.ts:203

Function gregorianToLunar

Parameters

Returns LunarDateValue

Example

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