PAN validation addition

Author: AYUSHI1007

README.md

@@ -194,7 +194,7 @@ Sanitizer                              | Description
 **trim(input [, chars])**              | trim characters (whitespace by default) from both sides of the input.
 **unescape(input)**                    | replace HTML encoded entities with `<`, `>`, `&`, `'`, `"`, `` ` ``, `\` and `/`.
 **whitelist(input, chars)**            | remove characters that do not appear in the whitelist. The characters are used in a RegExp and so you will need to escape some chars, e.g. `whitelist(input, '\\[\\]')`.
-
+**isPAN(str)** | check if the string is a valid Indian PAN number.
 ### XSS Sanitization
 
 XSS sanitization was removed from the library in [2d5d6999](https://github.com/validatorjs/validator.js/commit/2d5d6999541add350fb396ef02dc42ca3215049e).

src/index.js

@@ -129,7 +129,7 @@ import isLicensePlate from './lib/isLicensePlate';
 import isStrongPassword from './lib/isStrongPassword';
 
 import isVAT from './lib/isVAT';
-
+export { default as isPAN } from './lib/isPAN';
 const version = '13.15.35';
 
 const validator = {

src/lib/isPAN.js

@@ -0,0 +1,4 @@
+export default function isPAN(str) {
+  const panRegex = /^[A-Z]{5}[0-9]{4}[A-Z]$/;
+  return panRegex.test(str);
+}

test/validators/isPAN.test.js

@@ -0,0 +1,23 @@
+import isPAN from '../src/lib/isPAN';
+
+describe('isPAN', () => {
+  it('valid PAN', () => {
+    if (!isPAN('ABCDE1234F')) throw new Error();
+  });
+
+  it('invalid length', () => {
+    if (isPAN('ABCDE123F')) throw new Error();
+  });
+
+  it('lowercase should fail', () => {
+    if (isPAN('abcde1234f')) throw new Error();
+  });
+
+  it('wrong format', () => {
+    if (isPAN('1234ABCDE1')) throw new Error();
+  });
+
+  it('empty string', () => {
+    if (isPAN('')) throw new Error();
+  });
+});