Feature luhn (#3)

* luhn constraint

* luhn constraint

README.md

@@ -93,6 +93,7 @@ console.log(result);
   Financial and other Number Constraints:
   - [Currency](docs/Constraints/Currency.md)
   - [Issn](docs/Constraints/Issn.md)
+  - [Luhn](docs/Constraints/Luhn.md)
 
   Other constraints:
   - [Count](docs/Constraints/Count.md)
@@ -113,7 +114,6 @@ console.log(result);
 Investigate and add financial and other number constraints
 - Bic
 - CardScheme
-- Luhn
 - Iban
 - Isbn
 - Callback

docs/Constraints.md

@@ -47,10 +47,11 @@ Choice constraints:
 
 Financial and other Number Constraints:
 - [Currency](./Constraints/Currency.md)
+- [Luhn](./Constraints/Luhn.md)
+- [Issn](./Constraints/Issn.md)
 
 Other constraints:
 - [Count](./Constraints/Count.md)
-- [Issn](./Constraints/Issn.md)
 
 ## Create custom constraint
 

docs/Constraints/Luhn.md

@@ -0,0 +1,16 @@
+# Luhn
+This constraint is used to ensure that a credit card number passes the [Luhn algorithm](https://en.wikipedia.org/wiki/Luhn_algorithm). It is useful as a first step to validating a credit card: before communicating with a payment gateway.
+
+## Options
+
+##### message
+type: `string` default: `Invalid card number.`  
+The default message supplied when the value does not pass the Luhn check.
+
+| Parameter | Description |
+|---|---|
+| {{ value }} | The current (invalid) value
+
+##### trim
+type: `boolean` default: `true`  
+Trim provided value.  

src/Constraints/Luhn.js

@@ -0,0 +1,71 @@
+import AbstractConstraint from './AbstractConstraint';
+import { trim }           from '../Utils/functions';
+
+const MESSAGE_INVALID = 'Invalid card number.';
+
+export default class Luhn extends AbstractConstraint {
+    /**
+     * @param {{message: string, trim: boolean}} [options]
+     */
+    constructor(options) {
+        super(options);
+    }
+
+    /**
+     * @return {{message: string, trim: boolean}}
+     */
+    getDefaultOptions() {
+        return {
+            'trim': true,
+            'message': MESSAGE_INVALID,
+        };
+    }
+
+    /**
+     * Test provided value and return Error if occurs
+     *
+     * @param value
+     *
+     * @return {Error|undefined}
+     */
+    validate(value) {
+        if (this.options.trim) {
+            value = trim(value);
+        }
+
+        if (this.isEmptyValue(value)) {
+            return;
+        }
+
+        if (/[^0-9-\s]+/.test(value)) {
+            return this
+                .getViolationBuilder()
+                .setParameter('value', value)
+                .build(this.options.message);
+        }
+
+        let canonical = value.toString().replace(/\D/g, '');
+        let checkSum = 0;
+
+        for (let i = canonical.length - 1; i >= 0; i -= 2) {
+            checkSum += parseInt(canonical.charAt(i));
+        }
+
+        for (let i = canonical.length - 2; i >= 0; i -= 2) {
+            // checkSum += array_sum(str_split((int) $value[$i] * 2));
+            checkSum += (parseInt(canonical.charAt(i)) * 2)
+                .toString()
+                .split('')
+                .reduce((a, b) => {
+                    return parseInt(a) + parseInt(b);
+                }, 0);
+        }
+
+        if (0 === checkSum || 0 !== checkSum % 10) {
+            return this
+                .getViolationBuilder()
+                .setParameter('value', value)
+                .build(this.options.message);
+        }
+    }
+}

src/validator.js

@@ -33,6 +33,7 @@ import Regex              from './Constraints/Regex';
 import Range              from './Constraints/Range';
 import Locale             from './Constraints/Locale';
 import Issn               from './Constraints/Issn';
+import Luhn               from './Constraints/Luhn';
 import Validator          from './Validator/Validator';
 import Form               from './Validator/Form';
 
@@ -72,6 +73,7 @@ export default {
     Range: Range,
     Locale: Locale,
     Issn: Issn,
+    Luhn: Luhn,
     Validator: Validator,
     Form: Form,
 };

tests/Constraints/Luhn.spec.js

@@ -0,0 +1,67 @@
+import { Luhn } from '../../src/validator';
+
+const assert = require('assert');
+
+describe('Luhn', function () {
+    describe('#constructor()', function () {
+        it('empty configuration', function () {
+            new Luhn();
+        });
+    });
+
+    describe('#validate()', function () {
+        it('Valid', function () {
+            const object = new Luhn();
+
+            [
+                '42424242424242424242',
+                '378282246310005',
+                '371449635398431',
+                '378734493671000',
+                '5610591081018250',
+                '30569309025904',
+                '38520000023237',
+                '6011111111111117',
+                '6011000990139424',
+                '3530111333300000',
+                '3566002020360505',
+                '5555555555554444',
+                '3530-1113-3330-0000',
+                '3566002020360505',
+                '3566 0020 2036 0505',
+                '5555555555554444',
+                '5105105105105100',
+                '4111111111111111',
+                '4012888888881881',
+                '4222222222222',
+                '5019717010103742',
+                '6331101999990016',
+            ].forEach((code) => {
+                const e = object.validate(code);
+
+                assert.ok(typeof e === 'undefined', e);
+            });
+        });
+
+        it('Invalid', function () {
+            const object = new Luhn();
+
+            [
+                'foobar', 1, 100, 804, '804',
+                0,
+                '0',
+                '0000000000',
+                '00',
+                '1234567812345678',
+                '4222222222222222',
+                '0000000000000000',
+                '42-22222222222222'
+            ]
+                .forEach((code) => {
+                    const e = object.validate(code);
+
+                    assert.strictEqual(e.message, 'Invalid card number.');
+                });
+        });
+    });
+});