Function lastN

lastN(code: DocumentTypeCode, input: string, n?: number): string
Returns the trailing n characters of input after normalization.

Always operates on the canonical (normalized) form so that any user-visible formatting variation collapses to the same suffix. Common use case: index a last4 column for search alongside the encrypted full document.
Parameters
- code: DocumentTypeCode
  Document type whose normalization rules apply.
- input: string
  Raw user input.
- n: number = DEFAULT_N
  Number of trailing chars to return (default 4). Values <= 0 return the empty string. If the normalized form is shorter than n, the full normalized form is returned.
Returns string
The last n chars of the normalized form.
Throws
if code is not registered.
Example
```
import { lastN } from "nationid/pii";

lastN("BR_CNPJ", "12.345.678/0001-90");    // "0190"
lastN("BR_CNPJ", "12345678000190", 6);     // "000190"
lastN("SV_DUI",  "04567890-3");            // "8903"
```
- Defined in pii/last-n.ts:38