Use public suffix list for auth site labels

.changeset/tidy-domains-fix.md

@@ -0,0 +1,5 @@
+---
+"@onkernel/managed-auth-react": patch
+---
+
+Use the public suffix list to derive the site label shown on the initial auth screen.

packages/managed-auth-react/package.json

@@ -54,7 +54,8 @@
     "react-dom": ">=18"
   },
   "dependencies": {
-    "clsx": "^2.1.1"
+    "clsx": "^2.1.1",
+    "tldts": "7.4.15"
   },
   "devDependencies": {
     "@types/react": "^18",

packages/managed-auth-react/src/lib/profile-name.test.ts

@@ -0,0 +1,14 @@
+import { describe, expect, test } from "bun:test";
+import { extractPrimaryDomainLabel } from "./profile-name";
+
+describe("extractPrimaryDomainLabel", () => {
+  test("uses the registrable domain for subdomains of multi-label suffixes", () => {
+    expect(extractPrimaryDomainLabel("login.clalit.co.il")).toBe("clalit");
+    expect(extractPrimaryDomainLabel("auth.example.co.uk")).toBe("example");
+  });
+
+  test("uses the registrable domain for regular suffixes", () => {
+    expect(extractPrimaryDomainLabel("login.example.com")).toBe("example");
+    expect(extractPrimaryDomainLabel("example.com")).toBe("example");
+  });
+});

packages/managed-auth-react/src/lib/profile-name.ts

@@ -1,29 +1,4 @@
-const MULTI_PART_TLDS = new Set([
-  "co.uk",
-  "co.jp",
-  "co.kr",
-  "co.nz",
-  "co.za",
-  "co.in",
-  "co.id",
-  "co.th",
-  "com.au",
-  "com.br",
-  "com.cn",
-  "com.mx",
-  "com.tw",
-  "com.sg",
-  "com.ar",
-  "com.co",
-  "com.tr",
-  "org.uk",
-  "org.au",
-  "net.au",
-  "ac.uk",
-  "gov.uk",
-  "ne.jp",
-  "or.jp",
-]);
+import { parse } from "tldts";
 
 export function extractDomainName(targetDomain: string): string {
   return targetDomain
@@ -33,12 +8,6 @@ export function extractDomainName(targetDomain: string): string {
 }
 
 export function extractPrimaryDomainLabel(hostname: string): string {
-  const parts = hostname.split(".");
-  if (parts.length <= 1) return parts[0] || hostname;
-  if (parts.length === 2) return parts[0];
-  const lastTwo = parts.slice(-2).join(".");
-  const tldLength = MULTI_PART_TLDS.has(lastTwo.toLowerCase()) ? 2 : 1;
-  const primaryIndex = parts.length - tldLength - 1;
-  if (primaryIndex >= 0) return parts[primaryIndex];
-  return parts[0];
+  const domain = parse(hostname).domain;
+  return domain ? domain.split(".")[0] : hostname.split(".")[0] || hostname;
 }