fetch active users on mount

lib/live_beats/user_tracker.ex

@@ -1,7 +1,7 @@
 defmodule LiveBeats.UserTracker do
   use GenServer
   @pubsub LiveBeats.PubSub
-  @poll_interval :timer.seconds(5)
+  @poll_interval :timer.seconds(30)
 
   @doc """
   TODO
@@ -15,6 +15,10 @@ defmodule LiveBeats.UserTracker do
     GenServer.start_link(__MODULE__, opts, name: __MODULE__)
   end
 
+  def list_active_users() do
+    GenServer.call(__MODULE__, :list_users)
+  end
+
   def presence_joined(presence) do
     GenServer.call(__MODULE__, {:presence_joined, presence})
   end
@@ -28,6 +32,11 @@ defmodule LiveBeats.UserTracker do
     {:ok, schedule_updates(%{})}
   end
 
+  @impl true
+  def handle_call(:list_users, _from, state) do
+    {:reply, list_users(state), state}
+  end
+
   @impl true
   def handle_call({:presence_joined, presence}, _from, state) do
     {:reply, :ok, handle_join(state, presence)}
@@ -70,11 +79,14 @@ defmodule LiveBeats.UserTracker do
   end
 
   defp broadcast_updates(state) do
-    active_users =
-    state
-    |> Enum.map(fn {_key, value} -> value end)
-
-    Phoenix.PubSub.local_broadcast(@pubsub, topic(), {LiveBeats.UserTracker, %{active_users: active_users}})
+    Phoenix.PubSub.local_broadcast(
+      @pubsub,
+      topic(),
+      {LiveBeats.UserTracker, %{active_users: list_users(state)}}
+    )
   end
 
+  defp list_users(state) do
+    Enum.map(state, fn {_key, value} -> value end)
+  end
 end

lib/live_beats_web/live/nav.ex

@@ -1,14 +1,15 @@
 defmodule LiveBeatsWeb.Nav do
   import Phoenix.LiveView
+  alias LiveBeats.UserTracker
   alias LiveBeatsWeb.{ProfileLive, SettingsLive}
 
   def on_mount(:default, _params, _session, socket) do
     if connected?(socket) do
-      LiveBeats.UserTracker.subscribe()
+      UserTracker.subscribe()
     end
 
     socket
-     |> assign(:active_users, [])
+    |> assign(:active_users, UserTracker.list_active_users())
     |> assign(:region, System.get_env("FLY_REGION"))
     |> attach_hook(:active_tab, :handle_params, &handle_active_tab_params/3)
     |> attach_hook(:ping, :handle_event, &handle_event/3)
@@ -20,6 +21,7 @@ defmodule LiveBeatsWeb.Nav do
       {:cont, socket}
 
     end)
+
     {:cont, socket}
   end