Enum protocol

lib/phoenix_live_view/async_assign.ex

@@ -182,4 +182,47 @@ defmodule Phoenix.LiveView.AsyncAssign do
       socket
     end
   end
+
+  defimpl Enumerable, for: Phoenix.LiveView.AsyncAssign do
+    alias Phoenix.LiveView.AsyncAssign
+
+    def count(%AsyncAssign{result: result, loading?: false, error: nil, canceled?: false}),
+      do: Enum.count(result)
+
+    def count(%AsyncAssign{}), do: 0
+
+    def member?(%AsyncAssign{result: result, loading?: false, error: nil, canceled?: false}, item) do
+      Enum.member?(result, item)
+    end
+
+    def member?(%AsyncAssign{}, _item) do
+      raise RuntimeError, "cannot lookup member? while loading"
+    end
+
+    def reduce(
+          %AsyncAssign{result: result, loading?: false, error: nil, canceled?: false},
+          acc,
+          fun
+        ) do
+      do_reduce(result, acc, fun)
+    end
+
+    def reduce(%AsyncAssign{}, acc, _fun), do: acc
+
+    defp do_reduce(_list, {:halt, acc}, _fun), do: {:halted, acc}
+    defp do_reduce(list, {:suspend, acc}, fun), do: {:suspended, acc, &do_reduce(list, &1, fun)}
+    defp do_reduce([], {:cont, acc}, _fun), do: {:done, acc}
+
+    defp do_reduce([item | tail], {:cont, acc}, fun) do
+      do_reduce(tail, fun.(item, acc), fun)
+    end
+
+    def slice(%AsyncAssign{result: result, loading?: false, error: nil, canceled?: false}) do
+      fn start, length, step -> Enum.slice(result, start..(start + length - 1)//step) end
+    end
+
+    def slice(%AsyncAssign{}) do
+      fn _start, _length, _step -> [] end
+    end
+  end
 end

test/phoenix_live_view/integrations/assign_async_test.exs

@@ -76,4 +76,12 @@ defmodule Phoenix.LiveView.AssignAsyncTest do
       assert render_async(lv, 200) =~ "data: 123"
     end
   end
+
+  test "enum", %{conn: conn} do
+    {:ok, lv, _html} = live(conn, "/async?test=enum")
+
+    html = render_async(lv, 200)
+    assert html =~ "data: [1, 2, 3]"
+    assert html =~ "<div>1</div><div>2</div><div>3</div>"
+  end
 end

test/support/live_views/general.ex

@@ -355,6 +355,12 @@ defmodule Phoenix.LiveViewTest.AsyncLive do
     end
   end
 
+  on_mount {__MODULE__, :defaults}
+
+  def on_mount(:defaults, _params, _session, socket) do
+    {:cont, assign(socket, enum: false)}
+  end
+
   def render(assigns) do
     ~H"""
     <.live_component module={LC} id="lc" />
@@ -363,6 +369,9 @@ defmodule Phoenix.LiveViewTest.AsyncLive do
     <div :if={[email protected]? && @async.data.result == nil}>no data found</div>
     <div :if={[email protected]? && @async.data.result}>data: <%= inspect(@async.data.result) %></div>
     <div :if={err = @async.data.error}>error: <%= inspect(err) %></div>
+    <%= if @enum do %>
+      <div :for={i <- @async.data}><%= i %></div>
+    <% end %>
     """
   end
 
@@ -402,14 +411,20 @@ defmodule Phoenix.LiveViewTest.AsyncLive do
      end)}
   end
 
+  def mount(%{"test" => "enum"}, _session, socket) do
+    {:ok,
+     socket |> assign(enum: true) |> assign_async(:data, fn -> {:ok, %{data: [1, 2, 3]}} end)}
+  end
+
   def handle_info(:boom, _socket), do: exit(:boom)
 
   def handle_info(:cancel, socket), do: {:noreply, cancel_async(socket, :data)}
 
   def handle_info(:renew_canceled, socket) do
-    {:noreply, assign_async(socket, :data, fn ->
-      Process.sleep(100)
-      {:ok, %{data: 123}}
-    end)}
+    {:noreply,
+     assign_async(socket, :data, fn ->
+       Process.sleep(100)
+       {:ok, %{data: 123}}
+     end)}
   end
 end