feat(palindrome): check if string is a palindrome

README.md

@@ -173,6 +173,7 @@ Validator                               | Description
 **isVAT(str, countryCode)**             | check if the string is a [valid VAT number][VAT Number] if validation is available for the given country code matching [ISO 3166-1 alpha-2][ISO 3166-1 alpha-2]. <br/><br/>`countryCode` is one of `['AL', 'AR', 'AT', 'AU', 'BE', 'BG', 'BO', 'BR', 'BY', 'CA', 'CH', 'CL', 'CO', 'CR', 'CY', 'CZ', 'DE', 'DK', 'DO', 'EC', 'EE', 'EL', 'ES', 'FI', 'FR', 'GB', 'GT', 'HN', 'HR', 'HU', 'ID', 'IE', 'IL', 'IN', 'IS', 'IT', 'KZ', 'LT', 'LU', 'LV', 'MK', 'MT', 'MX', 'NG', 'NI', 'NL', 'NO', 'NZ', 'PA', 'PE', 'PH', 'PL', 'PT', 'PY', 'RO', 'RS', 'RU', 'SA', 'SE', 'SI', 'SK', 'SM', 'SV', 'TR', 'UA', 'UY', 'UZ', 'VE']`.
 **isWhitelisted(str, chars)**           | check if the string consists only of characters that appear in the whitelist `chars`.
 **matches(str, pattern [, modifiers])** | check if the string matches the pattern.<br/><br/>Either `matches('foo', /foo/i)` or `matches('foo', 'foo', 'i')`.
+**isPalindrome(str)**                   | check if the string is a [Palindrome](https://en.wikipedia.org/wiki/Palindrome).
 
 ## Sanitizers
 

src/index.js

@@ -128,6 +128,7 @@ import isLicensePlate from './lib/isLicensePlate';
 import isStrongPassword from './lib/isStrongPassword';
 
 import isVAT from './lib/isVAT';
+import isPalindrome from './lib/isPalindrome';
 
 const version = '13.12.0';
 
@@ -243,6 +244,7 @@ const validator = {
   isLicensePlate,
   isVAT,
   ibanLocales,
+  isPalindrome,
 };
 
 export default validator;

src/lib/isPalindrome.js

@@ -0,0 +1,9 @@
+import assertString from './util/assertString';
+
+export default function isPalindrome(str) {
+  assertString(str);
+  /* remove all special characters, spaces and make lowercase*/
+  let removeChar = str.replace(/[^A-Z0-9]/ig, "").toLowerCase();
+  let reverseStr = removeChar.split('').reverse().join('');
+  return removeChar === reverseStr;
+}

test/validators.test.js

@@ -15459,4 +15459,21 @@
       ],
     });
   });
+  it('should validate Palindromes', () => {
+    test({
+      validator: 'isPalindrome',
+      valid: [
+        'race car',
+        'A man, a plan, a canal. Panama',
+        'never odd or even',
+        'My age is 0, 0 si ega ym',
+        'civic',
+      ],
+      invalid: [
+        'not a palindrome',
+        'nope',
+        'name is alan'
+      ],
+    });
+  });
 });