isLuhn

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/IsLuhn'
 
 // -------------------------------------------------------------------------
 // Type checkers

src/decorator/string/IsLuhn.ts

@@ -0,0 +1,48 @@
+import { ValidationOptions } from '../ValidationOptions';
+import { buildMessage, ValidateBy } from '../common/ValidateBy';
+
+export const IS_LUHN = 'isLuhn';
+
+/**
+ * Verify the card number using the Luhn algorithm.
+ * The Luhn algorithm is a simple checksum formula used to validate a variety of identification numbers,
+ * such as credit card numbers.
+ */
+export function isLuhn(value: unknown): boolean {
+    if(typeof value != 'string') return false;
+    if(value.length == 0) return false;
+    let nCheck = 0;
+    if (/[0-9-\s]+/.test(value)) {
+        value = value.replace(/\D/g, '');
+
+        (value as string).split('').forEach((v, n) => {
+            let nDigit = parseInt(v, 10);
+
+            if (!(((value as string).length + n) % 2) && (nDigit *= 2) > 9) {
+                nDigit -= 9;
+            }
+
+            nCheck += nDigit;
+        });
+    }
+
+
+    return (nCheck % 10) === 0;
+}
+
+/**
+ * Verify the card number using the Luhn algorithm.
+ * */
+export function IsLuhn(validationOptions?: ValidationOptions): PropertyDecorator {
+  return ValidateBy(
+    {
+      name: IS_LUHN,
+      validator: {
+        validate: (value, args): boolean => isLuhn(value),
+        defaultMessage: buildMessage(eachPrefix => eachPrefix + '$property must be a valid card number', validationOptions),
+      },
+    },
+    validationOptions
+  );
+}
+

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

@@ -193,6 +193,7 @@ import {
   isTaxId,
   IsTaxId,
   IsISO4217CurrencyCode,
+  IsLuhn, isLuhn,
 } from '../../src/decorator/decorators';
 import { Validator } from '../../src/validation/Validator';
 import { ValidatorOptions } from '../../src/validation/ValidatorOptions';
@@ -789,6 +790,39 @@ describe('IsString', () => {
   });
 });
 
+describe("IsLuhn", ()=>{
+  const validValues = ['4532015112830366', '6011514433546201', '371449635398431', '6219861907174873'];
+  const invalidValues = ['4532015112830367', '1234567890123456', null, undefined, '', 6219861907174873];
+
+  class MyClass {
+    @IsLuhn()
+    someProperty: string;
+  }
+
+  it('should not fail if validator.validate said that its valid', () => {
+    return checkValidValues(new MyClass(), validValues);
+  });
+
+
+  it('should fail if validator.validate said that its invalid', () => {
+    return checkInvalidValues(new MyClass(), invalidValues);
+  });
+
+  it('should not fail if method in validator said that its valid', () => {
+    validValues.forEach(value => expect(isLuhn(value)).toBeTruthy());
+  });
+
+  it('should fail if method in validator said that its invalid', () => {
+    invalidValues.forEach(value => expect(isLuhn(value as any)).toBeFalsy());
+  });
+
+  it('should return error object with proper data', () => {
+    const validationType = 'isLuhn';
+    const message = 'someProperty must be a valid card number';
+    return checkReturnedError(new MyClass(), invalidValues, validationType, message);
+  });
+})
+
 describe('IsDateString', () => {
   const validValues = [
     '2017-06-06T17:04:42.081Z',