Function toSolar

toSolar(lunar): Date | -1
Converts a given lunar date to a solar (Gregorian) date. The function calculates the corresponding solar year, month, and day from the lunar date. If the lunar date is invalid or out of range, it returns -1.
Parameters
- lunar: LunarDate
  The lunar date object to convert. It should be a valid LunarDate object.
Returns Date | -1
A Date object representing the corresponding solar date, or -1 if the lunar date is invalid.
Example
```
// => 2025-01-30T00:00:00.000Z
toSolar({ year: 2025, month: 1, day: 30, isLeapMonth: false })
```
Example
```
// => -1
toSolar({ year: 1900, month: 1, day: 30, isLeapMonth: false })
```
- Defined in src/to-solar/index.ts:24