Feature/add is vat id decorator

README.md

@@ -884,6 +884,7 @@ isBoolean(value);
 | `@IsSurrogatePair()`                                   | Checks if the string contains any surrogate pairs chars.                                                                                                                                              |
 | `@IsTaxId()`                                           | Checks if the string is a valid tax ID. Default locale is `en-US`.                                                                                                                                    |
 | `@IsUrl(options?: IsURLOptions)`                       | Checks if the string is a URL.                                                                                                                                                                        |
+| `@IsVatId(countryCode: string)`                        | Checks if the string is a [valid VAT identification number for the country](https://taxation-customs.ec.europa.eu/vat-identification-numbers_en).                                                     |
 | `@IsMagnetURI()`                                       | Checks if the string is a [magnet uri format](https://en.wikipedia.org/wiki/Magnet_URI_scheme).                                                                                                       |
 | `@IsUUID(version?: UUIDVersion)`                       | Checks if the string is a UUID (version 3, 4, 5 or all ).                                                                                                                                             |
 | `@IsFirebasePushId()`                                  | Checks if the string is a [Firebase Push ID](https://firebase.googleblog.com/2015/02/the-2120-ways-to-ensure-unique_68.html)                                                                          |

src/decorator/decorators.ts

@@ -116,6 +116,7 @@ export * from './string/IsTimeZone';
 export * from './string/IsBase58';
 export * from './string/is-tax-id';
 export * from './string/is-iso4217-currency-code';
+export * from './string/IsVatId';
 
 // -------------------------------------------------------------------------
 // Type checkers

src/decorator/string/IsVatId.ts

@@ -0,0 +1,36 @@
+import { ValidationOptions } from '../ValidationOptions';
+import { buildMessage, ValidateBy } from '../common/ValidateBy';
+import isVatIdValidator from 'validator/lib/isVat';
+
+export const IS_VAT_ID = 'isVat';
+
+/**
+ * Checks if the string is a VAT (value-added tax) identification number.
+ * If given value is not a string, then it returns false.
+ */
+export function isVatId(value: unknown, countryCode: string): boolean {
+  try {
+    const isVatId = typeof value === 'string' && isVatIdValidator(value, countryCode);
+    return isVatId;
+  } catch (error) {
+    return false;
+  }
+}
+
+/**
+ * Checks if the string is a VAT (value-added tax) identification number.
+ * If given value is not a string, then it returns false.
+ */
+export function IsVatId(countryCode?: string, validationOptions?: ValidationOptions): PropertyDecorator {
+  return ValidateBy(
+    {
+      name: IS_VAT_ID,
+      constraints: [countryCode],
+      validator: {
+        validate: (value, args): boolean => isVatId(value, args?.constraints[0]),
+        defaultMessage: buildMessage(eachPrefix => eachPrefix + '$property must be a VAT ID', validationOptions),
+      },
+    },
+    validationOptions
+  );
+}

test/functional/validation-functions-and-decorators.spec.ts

@@ -193,6 +193,7 @@ import {
   isTaxId,
   IsTaxId,
   IsISO4217CurrencyCode,
+  IsVatId,
 } from '../../src/decorator/decorators';
 import { Validator } from '../../src/validation/Validator';
 import { ValidatorOptions } from '../../src/validation/ValidatorOptions';
@@ -4779,3 +4780,34 @@ describe('IsISO4217', () => {
     return checkInvalidValues(new MyClass(), invalidValues);
   });
 });
+
+describe('IsVatId', () => {
+  class MyClass {
+    @IsVatId('AT')
+    someProperty: string;
+  }
+
+  class MyInvalidClass {
+    @IsVatId('ZZ')
+    someProperty: string;
+  }
+
+  const validAtVatIds = ['U12345678', 'U01234567'];
+  const invalidAtVatIds = ['12345678', '000', 'abcdefgh'];
+
+  it('should not fail for a valid VAT id for valid country code', () => {
+    return checkValidValues(new MyClass(), validAtVatIds);
+  });
+
+  it('should fail for invalid country code', () => {
+    return checkInvalidValues(new MyInvalidClass(), validAtVatIds);
+  });
+
+  it('should fail for invalid VAT id for valid country code', () => {
+    return checkInvalidValues(new MyClass(), invalidAtVatIds);
+  });
+
+  it('should fail for invalid VAT id for invalid country code', () => {
+    return checkInvalidValues(new MyInvalidClass(), invalidAtVatIds);
+  });
+});