JS add_class persists after page is crashed

Phoenix Forum Questions / Help
1

I’m using JS commands to toggle a content. Like this minimal example

defmodule JsToggleBugWeb.Page do
  use JsToggleBugWeb, :live_view

  alias Phoenix.LiveView.JS

  def mount(_, _, socket) do
    {:ok, assign(socket, :visible, false)}
  end

  def handle_event("toggle", _, socket) do
    {:noreply, assign(socket, :visible, !socket.assigns.visible)}
  end

  def handle_event("raise", _, _socket), do: raise("Raise")

  def render(assigns) do
    ~H"""
    <div>
    <div><%= if @visible, do: "Visible", else: "Not visible" %></div>
    <div id="container" class={@visible && "visible1"}>Toggled content</div>
    <button phx-click={toggle(@visible)}>Toggle</button>
    <button phx-click="raise">Raise</button>
    </div>
    """
  end

  defp toggle(true = _is_visible?) do
    JS.remove_class("visible", to: "#container")
    |> JS.push("toggle")
  end

  defp toggle(false = _is_visible?) do
    JS.add_class("visible", to: "#container")
    |> JS.push("toggle")
  end
end

The problem is if page crashes (using “Raise” button here) the visible class persists after LV is re-mounted.

I don’t know if this is a bad usage from me, or it’s a bug. I can report this bug (I do have a POC repo for this) but first I wanted to make sure I’m not doing something wrong.

(I also do have a showcase video but it doesn’t allow video uploads here)