feat(rules): Added Issn rule

Author: ricardogobbosouza

README.md

@@ -158,6 +158,7 @@ The library can be loaded either as a standalone script, or through an [AMD](htt
 - [Isin](docs/isin.md)
 - [Iso8601](docs/iso8601.md)
 - [Isrc](docs/isrc.md)
+- [Issn](docs/issn.md)
 - [Iterable](docs/iterable.md)
 - [Json](docs/json.md)
 - [KeyNested](docs/key-nested.md)

docs/issn.md

@@ -0,0 +1,47 @@
+# Issn
+
+Validates if the input is [ISSN](https://pt.wikipedia.org/wiki/International_Standard_Serial_Number).
+
+Valid values:
+
+```js
+validator.issn(true).validate('2434-561X');
+validator.issn(true).validate('2434561X');
+validator.issn(true).validate('0378-5955');
+validator.issn(true).validate('03785955');
+validator.issn(false, true).validate('2434-561X');
+validator.issn(false, true).validate('2434-561x');
+validator.issn(false, true).validate('0378-5955');
+validator.issn(true, true).validate('2434-561X');
+validator.issn(true, true).validate('0378-5955');
+
+validator.issn().validate('0378-5955');
+validator.issn().validate('0000-0000');
+validator.issn().validate('2434-561X');
+validator.issn().validate('2434-561x');
+validator.issn().validate('01896016');
+validator.issn().validate('20905076');
+```
+
+Invalid values:
+
+```js
+validator.issn(true).validate('2434-561x');
+validator.issn(true).validate('2434561x');
+validator.issn(false, true).validate('2434561X');
+validator.issn(false, true).validate('2434561x');
+validator.issn(false, true).validate('03785955');
+validator.issn(true, true).validate('2434-561x');
+validator.issn(true, true).validate('2434561X');
+validator.issn(true, true).validate('2434561x');
+validator.issn(true, true).validate('03785955');
+
+validator.issn().validate('0378-5954');
+validator.issn().validate('0000-0001');
+validator.issn().validate('0378-123');
+validator.issn().validate('037-1234');
+validator.issn().validate('0');
+validator.issn().validate('2434-561c');
+validator.issn().validate('1684-5370');
+validator.issn().validate('19960791');
+```

src/rules/index.ts

@@ -76,6 +76,7 @@ export * from './isbn13';
 export * from './isin';
 export * from './iso8601';
 export * from './isrc';
+export * from './issn';
 export * from './iterable';
 export * from './json';
 export * from './key-nested';

src/rules/issn.ts

@@ -0,0 +1,40 @@
+import { AbstractRule } from './abstract-rule';
+
+export class Issn extends AbstractRule {
+
+    /**
+     * Issn.
+     */
+    public constructor(
+        public readonly caseSensitive: boolean = false,
+        public readonly requireHyphen: boolean = false
+    ) {
+        super();
+    }
+
+    /**
+     * Validate.
+     */
+    public validate(input: any): boolean {
+        const inputString: string = String(input);
+        const regex: string = `^\\d{4}-${(this.requireHyphen ? '' : '?')}\\d{3}[\\dX]$`;
+
+        if (!new RegExp(regex, this.caseSensitive ? undefined : 'i').test(inputString)) {
+            return false;
+        }
+
+        const issnDigits: string = inputString.replace('-', '');
+        let position: number = 8;
+        let checksum: number = 0;
+
+        for (const digit of issnDigits) {
+            const digitValue: number = digit.toUpperCase() === 'X' ? 10 : +digit;
+            checksum += digitValue * position;
+            --position;
+        }
+
+        return checksum % 11 === 0;
+    }
+}
+
+export default Issn;

test/rules/issn.ts

@@ -0,0 +1,70 @@
+import { assert } from 'chai';
+
+import { AbstractRule } from '../../src/rules/abstract-rule';
+import { Issn } from '../../src/rules/issn';
+
+describe('Issn', () => {
+
+    let issn: Issn;
+
+    beforeEach(() => {
+        issn = new Issn();
+    });
+
+    it('is rule', () => {
+        assert.instanceOf(issn, AbstractRule);
+    });
+
+    it('values is valid', () => {
+        assert.isTrue(new Issn(true).validate('2434-561X'));
+        assert.isTrue(new Issn(true).validate('2434561X'));
+        assert.isTrue(new Issn(true).validate('0378-5955'));
+        assert.isTrue(new Issn(true).validate('03785955'));
+        assert.isTrue(new Issn(false, true).validate('2434-561X'));
+        assert.isTrue(new Issn(false, true).validate('2434-561x'));
+        assert.isTrue(new Issn(false, true).validate('0378-5955'));
+        assert.isTrue(new Issn(true, true).validate('2434-561X'));
+        assert.isTrue(new Issn(true, true).validate('0378-5955'));
+
+        assert.isTrue(issn.validate('0378-5955'));
+        assert.isTrue(issn.validate('0000-0000'));
+        assert.isTrue(issn.validate('2434-561X'));
+        assert.isTrue(issn.validate('2434-561x'));
+        assert.isTrue(issn.validate('01896016'));
+        assert.isTrue(issn.validate('20905076'));
+    });
+
+    it('values is not valid', () => {
+        assert.isFalse(new Issn(true).validate('2434-561x'));
+        assert.isFalse(new Issn(true).validate('2434561x'));
+        assert.isFalse(new Issn(false, true).validate('2434561X'));
+        assert.isFalse(new Issn(false, true).validate('2434561x'));
+        assert.isFalse(new Issn(false, true).validate('03785955'));
+        assert.isFalse(new Issn(true, true).validate('2434-561x'));
+        assert.isFalse(new Issn(true, true).validate('2434561X'));
+        assert.isFalse(new Issn(true, true).validate('2434561x'));
+        assert.isFalse(new Issn(true, true).validate('03785955'));
+
+        assert.isFalse(issn.validate('0378-5954'));
+        assert.isFalse(issn.validate('0000-0001'));
+        assert.isFalse(issn.validate('0378-123'));
+        assert.isFalse(issn.validate('037-1234'));
+        assert.isFalse(issn.validate('0'));
+        assert.isFalse(issn.validate('2434-561c'));
+        assert.isFalse(issn.validate('1684-5370'));
+        assert.isFalse(issn.validate('19960791'));
+        assert.isFalse(issn.validate(''));
+        assert.isFalse(issn.validate(null));
+        assert.isFalse(issn.validate(undefined));
+        assert.isFalse(issn.validate(true));
+        assert.isFalse(issn.validate(false));
+        assert.isFalse(issn.validate([]));
+        assert.isFalse(issn.validate({}));
+        assert.isFalse(issn.validate(new Array('foo')));
+        assert.isFalse(issn.validate(new Object({foo: 'bar'})));
+
+        class Foo {}
+        assert.isFalse(issn.validate(new Foo()));
+    });
+
+});