Add Romanian postal code validator

CHANGELOG.md

@@ -4,6 +4,10 @@ All notable changes to this project are documented here. The format follows [Kee
 
 ## [Unreleased]
 
+### Added
+
+- `validatePostalCode` / `isValidPostalCode` for six-digit Romanian postal code format validation
+
 ## [0.1.0] - 2026-10-27
 
 ### Added

README.md

@@ -14,7 +14,7 @@
   <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** and **IBAN**) 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** and postal codes) with error messages you can show directly to users. Zero dependencies, fully typed, runs in Node and in the browser.
 
 ```bash
 npm install validro
@@ -60,7 +60,7 @@ type ValidationResult<T> =
   | { valid: false; error: string; data: null };
 ```
 
-Only need true or false? Use `isValidCnp`, `isValidCui` and `isValidIbanRo`.
+Only need true or false? Use `isValidCnp`, `isValidCui`, `isValidIbanRo` and `isValidPostalCode`.
 
 ## API
 
@@ -69,7 +69,8 @@ Only need true or false? Use `isValidCnp`, `isValidCui` and `isValidIbanRo`.
 | `validateCnp(cnp, now?)` | `ValidationResult<CnpInfo>`; `now` sets the date used to reject future birth dates |
 | `validateCui(cui)` | `ValidationResult<CuiInfo>` |
 | `validateIbanRo(iban)` | `ValidationResult<IbanInfo>` |
-| `isValidCnp`, `isValidCui`, `isValidIbanRo` | `boolean` |
+| `validatePostalCode(postalCode)` | `ValidationResult<PostalCodeInfo>`; exactly 6 digits |
+| `isValidCnp`, `isValidCui`, `isValidIbanRo`, `isValidPostalCode` | `boolean` |
 | `cnpControlDigit(first12)` | the CNP control digit |
 | `cuiControlDigit(body)` | the CUI control digit |
 | `ibanChecksumOk(iban)` | mod-97 check, works for any country |
@@ -109,3 +110,5 @@ Ideas and bugs are welcome in [issues](https://github.com/Robert-GeorgeDev/Valid
 ## License
 
 [MIT](LICENSE)
+
+

src/index.ts

@@ -4,5 +4,7 @@ export { validateCui, isValidCui, cuiControlDigit } from "./cui.js";
 export type { CuiInfo } from "./cui.js";
 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 { CNP_COUNTIES } from "./counties.js";
 export type { ValidationResult } from "./result.js";

src/postal-code.ts

@@ -0,0 +1,14 @@
+import { fail, ok, type ValidationResult } from "./result.js";
+
+export interface PostalCodeInfo {
+  postalCode: string;
+}
+
+/** Validates the six-digit format of a Romanian postal code. */
+export function validatePostalCode(input: string): ValidationResult<PostalCodeInfo> {
+  if (typeof input !== "string") return fail("Codul poștal trebuie să fie un șir de caractere");
+  if (!/^\d{6}$/.test(input)) return fail("Codul poștal trebuie să conțină exact 6 cifre");
+  return ok({ postalCode: input });
+}
+
+export const isValidPostalCode = (input: string): boolean => validatePostalCode(input).valid;

test/postal-code.test.ts

@@ -0,0 +1,11 @@
+import { describe, expect, it } from "vitest";
+import { isValidPostalCode, validatePostalCode } from "../src/postal-code.js";
+
+describe("Romanian postal code", () => {
+  it("accepts exactly six digits and rejects other formats", () => {
+    expect(validatePostalCode("010101")).toEqual({ valid: true, error: null, data: { postalCode: "010101" } });
+    expect(isValidPostalCode("12345")).toBe(false);
+    expect(isValidPostalCode("1234567")).toBe(false);
+    expect(isValidPostalCode("12345a")).toBe(false);
+  });
+});