From 95a563b22a8c90b022d8f811ab6c9dd83510fc76 Mon Sep 17 00:00:00 2001
From: iamsivin <iamsivin@gmail.com>
Date: Wed, 30 Jul 2025 08:57:33 +0530
Subject: [PATCH] feat: Add `isValidDomain` helper for validation

---
 package.json     |  2 +-
 src/index.ts     |  3 ++-
 src/url.ts       | 15 +++++++++++++++
 test/url.test.ts | 45 ++++++++++++++++++++++++++++++++++++++++++++-
 4 files changed, 62 insertions(+), 3 deletions(-)

diff --git a/package.json b/package.json
index 2089379..f614f58 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@chatwoot/utils",
-  "version": "0.0.48",
+  "version": "0.0.49",
   "description": "Chatwoot utils",
   "private": false,
   "license": "MIT",
diff --git a/src/index.ts b/src/index.ts
index 5cf5eb6..1f04d59 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -12,7 +12,7 @@ import {
   formatNumber,
 } from './helpers';
 
-import { toURL, isSameHost } from './url';
+import { toURL, isSameHost, isValidDomain } from './url';
 
 import { getRecipients } from './email';
 
@@ -62,6 +62,7 @@ export {
   splitName,
   toURL,
   isSameHost,
+  isValidDomain,
   trimContent,
   downloadFile,
   getFileInfo,
diff --git a/src/url.ts b/src/url.ts
index ac9a116..91aa012 100644
--- a/src/url.ts
+++ b/src/url.ts
@@ -50,3 +50,18 @@ export const isSameHost = (
     return false;
   }
 };
+
+/**
+ * Check if a string is a valid domain name.
+ * An empty string is allowed and considered valid.
+ *
+ * @param domain Domain to validate.
+ * @returns Whether the domain matches the rules.
+ */
+export const isValidDomain = (domain: string): boolean => {
+  if (domain === '') return true;
+
+  const domainRegex = /^(?!-)(?!.*--)[\p{L}0-9-]{1,63}(?<!-)(?:\.(?!-)(?!.*--)[\p{L}0-9-]{1,63}(?<!-))*\.[\p{L}]{2,63}$/u;
+
+  return domainRegex.test(domain) && domain.length <= 253;
+};
diff --git a/test/url.test.ts b/test/url.test.ts
index c920d7e..aeb1afa 100644
--- a/test/url.test.ts
+++ b/test/url.test.ts
@@ -1,4 +1,4 @@
-import { toURL, isSameHost } from '../src';
+import { toURL, isSameHost, isValidDomain } from '../src';
 
 describe('toURL', () => {
   it('returns null for falsy inputs', () => {
@@ -80,3 +80,46 @@ describe('isSameHost', () => {
     expect(isSameHost(url1, url3)).toBe(false);
   });
 });
+
+describe('#isValidDomain', () => {
+  it('should return true for valid domains', () => {
+    expect(isValidDomain('')).toBe(true);
+    expect(isValidDomain('google.com')).toBe(true);
+    expect(isValidDomain('example.org')).toBe(true);
+    expect(isValidDomain('test.net')).toBe(true);
+    expect(isValidDomain('www.google.com')).toBe(true);
+    expect(isValidDomain('api.example.org')).toBe(true);
+    expect(isValidDomain('deep.nested.subdomain.com')).toBe(true);
+    expect(isValidDomain('my-site.com')).toBe(true);
+    expect(isValidDomain('test-domain.co.uk')).toBe(true);
+    expect(isValidDomain('123domain.org')).toBe(true);
+    expect(isValidDomain('测试.网络')).toBe(true);
+    expect(isValidDomain('пример.рф')).toBe(true);
+    expect(isValidDomain('example.co.uk')).toBe(true);
+  });
+
+  it('should return false for invalid domains', () => {
+    const longDomain = 'a'.repeat(250) + '.com';
+    expect(isValidDomain('localhost')).toBe(false);
+    expect(isValidDomain('example.com!')).toBe(false);
+    expect(isValidDomain('test@domain.com')).toBe(false);
+    expect(isValidDomain('domain with spaces.com')).toBe(false);
+    expect(isValidDomain('test_domain.com')).toBe(false);
+    expect(isValidDomain('example..com')).toBe(false);
+    expect(isValidDomain('..example.com')).toBe(false);
+    expect(isValidDomain('example.com..')).toBe(false);
+    expect(isValidDomain('-example-.com')).toBe(false);
+    expect(isValidDomain(longDomain)).toBe(false);
+    expect(isValidDomain('192.168.1.1')).toBe(false);
+    expect(isValidDomain('127.0.0.1')).toBe(false);
+    expect(isValidDomain('example.com/path/to/page')).toBe(false);
+    expect(isValidDomain('http://example.com')).toBe(false);
+    expect(isValidDomain('https://example.com')).toBe(false);
+    expect(isValidDomain((null as unknown) as string)).toBe(false);
+    expect(isValidDomain((undefined as unknown) as string)).toBe(false);
+    expect(isValidDomain((123 as unknown) as string)).toBe(false);
+    expect(isValidDomain(({} as unknown) as string)).toBe(false);
+    expect(isValidDomain(([] as unknown) as string)).toBe(false);
+    expect(isValidDomain('   ')).toBe(false);
+  });
+});