feat: add Luhn validator constraint

Tests/app/src/Form/TestForm.php

@@ -118,6 +118,11 @@ public function buildForm(FormBuilderInterface $builder, array $options): void
                     new Constraints\Url(message: 'Please fill valid url'),
                 ],
             ])
+            ->add('luhn', TextType::class, [
+                'constraints' => [
+                    new Constraints\Luhn(message: 'Please fill valid card number'),
+                ],
+            ])
 
             ->add('save', SubmitType::class)
         ;

cypress/integration/form_spec.js

@@ -209,5 +209,17 @@ context('JsFormValidatorBundle', () => {
             getErrors(fieldId).should('have.length', 0);
         });
 
+        it('test luhn', () => {
+            const fieldId = 'test_form_luhn';
+            cy.get('#' + fieldId).type('1234567890').should('have.value', '1234567890');
+            submitForm();
+            getErrors(fieldId).should('have.length', 1);
+            cy.get('.form-error-test-form-luhn').contains('Please fill valid card number');
+
+            cy.get('#' + fieldId).clear().type('79927398713').should('have.value', '79927398713');
+            submitForm();
+            getErrors(fieldId).should('have.length', 0);
+        });
+
     });
 });

src/Resources/public/js/constraints/Luhn.js

@@ -0,0 +1,54 @@
+//noinspection JSUnusedGlobalSymbols
+/**
+ * Validates that a value passes the Luhn algorithm (typically a credit card number)
+ * @constructor
+ * @author dalexandre@jolicode.com
+ */
+export default function SymfonyComponentValidatorConstraintsLuhn() {
+    this.message = '';
+
+    this.validate = function (value) {
+        var errors = [];
+        var f = FpJsFormValidator;
+
+        if (f.isValueEmty(value)) {
+            return errors;
+        }
+
+        // Work with strings only
+        var strValue = String(value);
+
+        // Check if the value contains only digits
+        if (!/^\d+$/.test(strValue)) {
+            errors.push(this.message.replace('{{ value }}', FpJsBaseConstraint.formatValue(value)));
+            return errors;
+        }
+
+        // Luhn algorithm
+        var checkSum = 0;
+        var length = strValue.length;
+
+        for (var i = length - 1; i >= 0; i--) {
+            var digit = parseInt(strValue.charAt(i), 10);
+
+            if ((i % 2) ^ (length % 2)) {
+                // Add every second digit starting from the last
+                checkSum += digit;
+            } else {
+                // Double every second digit and add it to the check sum
+                // For doubles greater than 9, sum the individual digits
+                var doubled = digit * 2;
+                checkSum += (doubled >= 10) ? (Math.floor(doubled / 10) + (doubled % 10)) : doubled;
+            }
+        }
+
+        // Checksum must be non-zero and a multiple of 10
+        if (0 === checkSum || 0 !== checkSum % 10) {
+            errors.push(this.message.replace('{{ value }}', FpJsBaseConstraint.formatValue(value)));
+        }
+
+        return errors;
+    }
+}
+
+window.SymfonyComponentValidatorConstraintsLuhn = SymfonyComponentValidatorConstraintsLuhn;

src/Resources/public/js/constraints/Luhn.test.js

@@ -0,0 +1,36 @@
+import '../FpJsFormValidator';
+import SymfonyComponentValidatorConstraintsLuhn from './Luhn';
+
+const constraintsLuhn = new SymfonyComponentValidatorConstraintsLuhn();
+constraintsLuhn.message = '{{ value }} is not a valid card number';
+
+test.each([
+    // Valid Luhn numbers
+    ['79927398713', []], // Valid Luhn checksum
+    ['4532015112830366', []], // Example credit card number
+    ['6011111111111117', []], // Example credit card number
+    ['378282246310005', []], // Example AMEX number
+    ['5105105105105100', []], // Example MasterCard number
+    ['4111111111111111', []], // Example Visa number
+
+    // Invalid Luhn numbers
+    ['79927398712', ['"79927398712" is not a valid card number']],
+    ['1234567890123456', ['"1234567890123456" is not a valid card number']],
+    ['1111111111111111', ['"1111111111111111" is not a valid card number']],
+    ['0', ['"0" is not a valid card number']], // Single zero fails Luhn
+    ['00', ['"00" is not a valid card number']], // Multiple zeros fail Luhn
+
+    // Non-numeric strings
+    ['abc', ['"abc" is not a valid card number']],
+    ['4532-0151-1283-0366', ['"4532-0151-1283-0366" is not a valid card number']], // Contains dashes
+    ['4532 0151 1283 0366', ['"4532 0151 1283 0366" is not a valid card number']], // Contains spaces
+    ['', []], // Empty string
+    [null, []], // null
+    [undefined, []], // undefined
+    [false, []], // false
+])(
+    'SymfonyComponentValidatorConstraintsLuhn',
+    (value, expected) => {
+        expect(constraintsLuhn.validate(value)).toStrictEqual(expected);
+    },
+);

src/Resources/public/js/constraints/index.js

@@ -16,6 +16,7 @@ import './IsTrue.js';
 import './Length.js';
 import './LessThan.js';
 import './LessThanOrEqual.js';
+import './Luhn.js';
 import './NotBlank.js';
 import './NotEqualTo.js';
 import './NotIdenticalTo.js';