Function isValidNic

isValidNic(nic: unknown, options?: NicOptions): boolean
Checks whether an input string is a valid Sri Lankan NIC (old or new format).
Parameters
- nic: unknown
  NIC number, old (9 digits + V/X) or new (12 digits). Strings and finite numbers are accepted; other types return a failure without throwing.
- Optionaloptions: NicOptions
  Optional { referenceDate } used for age and future-date checks. Defaults to today.
Returns boolean
true for a valid old- or new-format NIC, otherwise false.
Example
```
isValidNic('921234567V'); // true
isValidNic('199212304567'); // true
isValidNic('9212345678'); // false
```
- Defined in nic/validator.ts:20