Extract visitor ID management into visitor.ts

Signed-off-by: Émile Ré <emile@getprobo.com>

packages/cookie-banner/src/client.ts

@@ -15,6 +15,7 @@
 import { getConsentCookie, setConsentCookie } from "./cookie";
 import { NotFoundError } from "./errors";
 import { fetchJSON } from "./http";
+import { getOrCreateVisitorId } from "./visitor";
 
 export interface CookieItem {
   name: string;
@@ -60,31 +61,6 @@ export interface CookieBannerClientOptions {
   baseUrl: string;
 }
 
-const STORAGE_KEY_PREFIX = "probo_consent";
-
-function getOrCreateVisitorId(bannerId: string): string {
-  const key = `${STORAGE_KEY_PREFIX}:${bannerId}:vid`;
-
-  try {
-    const stored = localStorage.getItem(key);
-    if (stored) {
-      return stored;
-    }
-  } catch {
-    // localStorage unavailable
-  }
-
-  const id = crypto.randomUUID();
-
-  try {
-    localStorage.setItem(key, id);
-  } catch {
-    // localStorage unavailable
-  }
-
-  return id;
-}
-
 export class CookieBannerClient {
   private readonly baseUrl: string;
   private readonly bannerId: string;

packages/cookie-banner/src/visitor.ts

@@ -0,0 +1,38 @@
+// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+const STORAGE_KEY_PREFIX = "probo_consent";
+
+export function getOrCreateVisitorId(bannerId: string): string {
+  const key = `${STORAGE_KEY_PREFIX}:${bannerId}:vid`;
+
+  try {
+    const stored = localStorage.getItem(key);
+    if (stored) {
+      return stored;
+    }
+  } catch {
+    // localStorage unavailable
+  }
+
+  const id = crypto.randomUUID();
+
+  try {
+    localStorage.setItem(key, id);
+  } catch {
+    // localStorage unavailable
+  }
+
+  return id;
+}