Initial commit

src/device/DeviceId.ts

@@ -0,0 +1,29 @@
+/**
+ * Device ID provider — generates and persists a unique device identifier.
+ *
+ * Uses `crypto.randomUUID()` (available in all evergreen browsers) and
+ * stores the generated UUID in localStorage under `rudder_device_id`.
+ */
+
+const STORAGE_KEY = 'rudder_device_id';
+
+/**
+ * Returns the stored device ID or creates a new one if none exists.
+ * The device ID is persisted in localStorage and survives page reloads.
+ */
+export function getOrCreateDeviceId(): string {
+  try {
+    const existing = localStorage.getItem(STORAGE_KEY);
+    if (existing) return existing;
+  } catch {
+    // localStorage unavailable — generate ephemeral ID.
+  }
+
+  const id = crypto.randomUUID();
+  try {
+    localStorage.setItem(STORAGE_KEY, id);
+  } catch {
+    // Storage unavailable — ID will be ephemeral for this session.
+  }
+  return id;
+}