Behaviour for StarView-enabled Phoenix controllers.

Use use StarView, :controller in your AppWeb.controller/0 macro, then implement callbacks with @impl StarView:

Lifecycle

1. mount/2 — Sets up initial signals and assigns for the page load.
2. render/1 — Renders the HEEx template. Use init_signals/1 to emit the data-signals attribute for the initial client state.
3. handle_event/3 — Called by StarView.Phoenix.Dispatch when a Datastar action fires. The dispatcher starts the SSE response before this callback and flushes tracked signals afterwards.

Example

@impl StarView
def mount(conn, _params) do
  conn
  |> signal(:count, 0)
  |> signal(:step, 1)
end

@impl StarView
def render(assigns) do
  ~H"""
  <div data-signals={init_signals(@conn)}>
    <button data-on:click={post("increment")}>+</button>
    <span data-text="$count">{@count}</span>
  </div>
  """
end

@impl StarView
def handle_event("increment", signals, conn) do
  conn
  |> signal(:count, Map.get(signals, "count", 0) + 1)
end