add datetime view helper

lib/cannery_web.ex

@@ -98,6 +98,7 @@ defmodule CanneryWeb do
 
       import CanneryWeb.ErrorHelpers
       import CanneryWeb.Gettext
+      import CanneryWeb.ViewHelpers
       alias CanneryWeb.Router.Helpers, as: Routes
     end
   end

lib/cannery_web/views/view_helpers.ex

@@ -0,0 +1,34 @@
+defmodule CanneryWeb.ViewHelpers do
+  @moduledoc """
+  Contains common helpers that can be used in liveviews and regular views. These
+  are automatically imported into any Phoenix View using `use CanneryWeb,
+  :view`
+  """
+
+  import Phoenix.LiveView.Helpers
+
+  @doc """
+  Returns a <time> element that renders the naivedatetime in the user's local
+  timezone with Alpine.js
+  """
+  @spec display_datetime(NaiveDateTime.t()) :: Phoenix.LiveView.Rendered.t()
+  def display_datetime(datetime) do
+    assigns = %{
+      datetime: datetime |> DateTime.from_naive!("Etc/UTC") |> DateTime.to_iso8601(:extended)
+    }
+
+    ~H"""
+    <time
+      datetime={datetime}
+      x-data={"{
+        date:
+          Intl.DateTimeFormat([], {dateStyle: 'short', timeStyle: 'long'})
+            .format(new Date(\"#{datetime}\"))
+      }"}
+      x-text="date"
+    >
+      <%= datetime %>
+    </time>
+    """
+  end
+end