Function getEndOfYear

getEndOfYear(date?: Date): undefined | Date
Returns the end year date of the given date
Parameters
- Optionaldate: Date
  the date to inspect
Returns undefined | Date
the end year date of the given date
Author
David Hsing
Example
```
getEndOfYear(new Date(2023, 8, 30));    // Date(2023, 11, 31, 23, 59, 59)
```