feat: add Romanian licence plate validation

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project are documented here. The format follows [Kee
 
 ## [Unreleased]
 
+### Added
+
+- `validatePlate` / `isValidPlate` for Romanian registration plates, including county lookup and input normalization
+
 ## [0.1.0] - 2026-10-27
 
 ### Added

README.md

@@ -13,7 +13,7 @@
   <a href="https://robert-georgedev.github.io/ValidRO/"><strong>Try it in your browser</strong></a>
 </p>
 
-Validate and decode Romanian identifiers (**CNP**, **CUI/CIF**, **IBAN** and postal codes) with error messages you can show directly to users. Zero dependencies, fully typed, runs in Node and in the browser.
+Validate and decode Romanian identifiers (**CNP**, **CUI/CIF**, **IBAN**, postal codes and licence plates) with error messages you can show directly to users. Zero dependencies, fully typed, runs in Node and in the browser.
 
 ```bash
 npm install github:Robert-GeorgeDev/ValidRO
@@ -25,13 +25,13 @@ The package is not on the npm registry yet; this installs it straight from GitHu
 
 - **Current rules.** Accepts county code `70`, which the civil-status system (SIIEASC) now assigns to newly generated CNPs. Many older validators reject these valid codes.
 - **Explains the error.** Messages are in Romanian and say what is wrong: `Cifra de control este greșită (așteptat 7)`.
-- **Decodes, not just validates.** Sex, birth date, county, bank code.
+- **Decodes, not just validates.** Sex, birth date, county, bank code and plate county.
 - **Private.** Everything runs locally. Nothing is sent anywhere.
 
 ## Usage
 
 ```ts
-import { validateCnp, validateCui, validateIbanRo } from "validro";
+import { validateCnp, validateCui, validateIbanRo, validatePlate } from "validro";
 
 validateCnp("3000101221147");
 // {
@@ -51,6 +51,12 @@ validateIbanRo("ro49 aaaa 1b31 0075 9384 0000");
 // { valid: true, error: null,
 //   data: { iban: "RO49AAAA1B31007593840000", formatted: "RO49 AAAA 1B31 0075 9384 0000",
 //           bankCode: "AAAA", treasury: false } }
+
+validatePlate("cj-12 abc");
+// { valid: true, error: null, data: { plate: "CJ12ABC", countyCode: "CJ", county: "Cluj" } }
+
+validatePlate("B 123 ABC");
+// { valid: true, error: null, data: { plate: "B123ABC", countyCode: "B", county: "București" } }
 ```
 
 Every `validate*` function returns the same shape, so you can handle all of them the same way:
@@ -61,7 +67,7 @@ type ValidationResult<T> =
   | { valid: false; error: string; data: null };
 ```
 
-Only need true or false? Use `isValidCnp`, `isValidCui`, `isValidIbanRo` and `isValidPostalCode`.
+Only need true or false? Use `isValidCnp`, `isValidCui`, `isValidIbanRo`, `isValidPostalCode` and `isValidPlate`.
 
 ## API
 
@@ -71,11 +77,13 @@ Only need true or false? Use `isValidCnp`, `isValidCui`, `isValidIbanRo` and `is
 | `validateCui(cui)` | `ValidationResult<CuiInfo>` |
 | `validateIbanRo(iban)` | `ValidationResult<IbanInfo>` |
 | `validatePostalCode(postalCode)` | `ValidationResult<PostalCodeInfo>`; exactly 6 digits |
-| `isValidCnp`, `isValidCui`, `isValidIbanRo`, `isValidPostalCode` | `boolean` |
+| `validatePlate(plate)` | `ValidationResult<PlateInfo>`; normalized plate and county details |
+| `isValidCnp`, `isValidCui`, `isValidIbanRo`, `isValidPostalCode`, `isValidPlate` | `boolean` |
 | `cnpControlDigit(first12)` | the CNP control digit |
 | `cuiControlDigit(body)` | the CUI control digit |
 | `ibanChecksumOk(iban)` | mod-97 check, works for any country |
-| `CNP_COUNTIES` | county codes and names |
+| `CNP_COUNTIES` | county codes and names for CNPs |
+| `PLATE_COUNTIES` | registration-plate county codes and names |
 
 ## What is checked
 
@@ -85,6 +93,7 @@ Only need true or false? Use `isValidCnp`, `isValidCui`, `isValidIbanRo` and `is
 | CUI / CIF | optional `RO` prefix, 2–10 digits, no leading zero, control digit (key `753217532`) |
 | IBAN (RO) | 24 characters: `RO`, 2 check digits, 4-letter bank code, 16 alphanumerics, ISO 13616 mod-97 |
 | Postal code | exactly 6 digits |
+| Licence plate | known Romanian county code, 2 digits and 3 letters; București (`B`) accepts 2 or 3 digits; spaces, dots and dashes are ignored |
 
 Spaces, dots and dashes in the input are ignored.
 
@@ -102,7 +111,7 @@ All examples in this repository are fictitious: sample CNPs use birth dates in t
 
 ## Roadmap
 
-- [ ] Romanian licence plates
+- [x] Romanian licence plates
 - [ ] Phone numbers, normalized to `+40`
 - [x] Postal codes
 - [ ] Python port

src/index.ts

@@ -6,5 +6,7 @@ export { validateIbanRo, isValidIbanRo, ibanChecksumOk } from "./iban.js";
 export type { IbanInfo } from "./iban.js";
 export { validatePostalCode, isValidPostalCode } from "./postal-code.js";
 export type { PostalCodeInfo } from "./postal-code.js";
+export { validatePlate, isValidPlate, PLATE_COUNTIES } from "./plate.js";
+export type { PlateInfo } from "./plate.js";
 export { CNP_COUNTIES } from "./counties.js";
 export type { ValidationResult } from "./result.js";

src/plate.ts

@@ -0,0 +1,79 @@
+import { clean, fail, ok, type ValidationResult } from "./result.js";
+
+export const PLATE_COUNTIES: Readonly<Record<string, string>> = Object.freeze({
+  AB: "Alba",
+  AR: "Arad",
+  AG: "Argeș",
+  BC: "Bacău",
+  BH: "Bihor",
+  BN: "Bistrița-Năsăud",
+  BT: "Botoșani",
+  BV: "Brașov",
+  BR: "Brăila",
+  BZ: "Buzău",
+  CS: "Caraș-Severin",
+  CL: "Călărași",
+  CT: "Constanța",
+  CV: "Covasna",
+  DB: "Dâmbovița",
+  DJ: "Dolj",
+  GL: "Galați",
+  GR: "Giurgiu",
+  GJ: "Gorj",
+  HR: "Harghita",
+  HD: "Hunedoara",
+  IL: "Ialomița",
+  IS: "Iași",
+  IF: "Ilfov",
+  MM: "Maramureș",
+  MH: "Mehedinți",
+  MS: "Mureș",
+  NT: "Neamț",
+  OT: "Olt",
+  PH: "Prahova",
+  SM: "Satu Mare",
+  SJ: "Sălaj",
+  SB: "Sibiu",
+  SV: "Suceava",
+  TR: "Teleorman",
+  TM: "Timiș",
+  TL: "Tulcea",
+  VS: "Vaslui",
+  VL: "Vâlcea",
+  VN: "Vrancea",
+  B: "București",
+});
+
+export interface PlateInfo {
+  plate: string;
+  countyCode: string;
+  county: string;
+}
+
+/**
+ * Validates the standard Romanian registration-plate format.
+ * Spaces, dots and dashes are ignored; the returned plate is uppercase and compact.
+ */
+export function validatePlate(input: string): ValidationResult<PlateInfo> {
+  if (typeof input !== "string") return fail("Numărul de înmatriculare trebuie să fie un șir de caractere");
+
+  const plate = clean(input).toUpperCase();
+  const bucharestMatch = /^B(\d{2,3})([A-Z]{3})$/.exec(plate);
+  const countyMatch = /^([A-Z]{2})(\d{2})([A-Z]{3})$/.exec(plate);
+
+  let countyCode: string;
+  if (bucharestMatch) {
+    countyCode = "B";
+  } else if (countyMatch) {
+    countyCode = countyMatch[1];
+  } else {
+    return fail("Numărul trebuie să conțină indicativul județului, 2 cifre (3 pentru București sunt permise) și 3 litere");
+  }
+
+  const county = PLATE_COUNTIES[countyCode];
+  if (!county) return fail("Indicativul județului nu este valid");
+
+  return ok({ plate, countyCode, county });
+}
+
+export const isValidPlate = (input: string): boolean => validatePlate(input).valid;

test/plate.test.ts

@@ -0,0 +1,52 @@
+import { describe, expect, it } from "vitest";
+import { isValidPlate, validatePlate } from "../src/index.js";
+
+describe("validatePlate", () => {
+  it("accepts county and Bucharest plates and returns county data", () => {
+    expect(validatePlate("CJ 12 ABC")).toEqual({
+      valid: true,
+      error: null,
+      data: { plate: "CJ12ABC", countyCode: "CJ", county: "Cluj" },
+    });
+    expect(validatePlate("B 123 ABC").data).toEqual({
+      plate: "B123ABC",
+      countyCode: "B",
+      county: "București",
+    });
+    expect(validatePlate("B-12-ABC").valid).toBe(true);
+  });
+
+  it("normalizes separators and letter case", () => {
+    expect(validatePlate(" cj-12 abc ").data).toEqual({
+      plate: "CJ12ABC",
+      countyCode: "CJ",
+      county: "Cluj",
+    });
+    expect(validatePlate("b.123.abc").data?.plate).toBe("B123ABC");
+  });
+
+  it("accepts known county codes", () => {
+    expect(isValidPlate("AB12ABC")).toBe(true);
+    expect(isValidPlate("IF12ABC")).toBe(true);
+    expect(isValidPlate("VN12ABC")).toBe(true);
+  });
+
+  it.each([
+    "CJ1ABC",
+    "CJ1234ABC",
+    "CJ12AB",
+    "CJ12ABCD",
+    "XX12ABC",
+    "B1ABC",
+    "B1234ABC",
+    "B12AB",
+    "B123ABCD",
+    "12ABC",
+  ])("rejects invalid plate %s", (plate) => {
+    expect(isValidPlate(plate)).toBe(false);
+  });
+
+  it("explains malformed input", () => {
+    expect(validatePlate("CJ1ABC").error).toContain("indicativul județului");
+  });
+});