Function formatNic

formatNic(
    nic: unknown,
    style?: NicFormatStyle,
    options?: NicOptions,
): string | null
Formats a Sri Lankan NIC cleanly.
Parameters
- nic: unknown
  NIC number, old or new format.
- Optionalstyle: NicFormatStyle
  Output style: 'old', 'new', 'spaced-old', or 'spaced-new'. Defaults to the input's own format.
- Optionaloptions: NicOptions
  Optional { referenceDate } used for age and future-date checks. Defaults to today.
Returns string | null
The formatted NIC, or null if the input is invalid.
Example
```
formatNic('921234567v'); // '921234567V'
formatNic('921234567V', 'new'); // '199212304567'
formatNic('199212304567', 'spaced-new'); // '1992 123 0456 7'
```
- Defined in nic/formatter.ts:22