Ensure textarea content is not trimmed in TreeDOM (#3935)

* test: add test for multiline textarea rendering

* Ensure textarea content is not trimmed in TreeDOM

Closes #3928.

---------

Co-authored-by: Shunji Lin <[email protected]>

Author: SteffenDE

lib/phoenix_live_view/test/client_proxy.ex

@@ -1431,7 +1431,7 @@ defmodule Phoenix.LiveViewTest.ClientProxy do
   end
 
   defp form_defaults("textarea", node, name, acc) do
-    value = TreeDOM.to_text(node)
+    value = TreeDOM.to_text(node, false)
 
     if value == "" do
       Plug.Conn.Query.decode_each({name, ""}, acc)

lib/phoenix_live_view/test/tree_dom.ex

@@ -62,12 +62,19 @@ defmodule Phoenix.LiveViewTest.TreeDOM do
   @doc """
   Returns the text representation of the node, removing extra whitespace.
   """
-  def to_text(tree) do
-    tree
-    |> node_to_text()
-    |> Enum.join()
-    |> String.replace(~r/[\s]+/, " ")
-    |> String.trim()
+  def to_text(tree, trim \\ true) do
+    text =
+      tree
+      |> node_to_text()
+      |> Enum.join()
+
+    if trim do
+      text
+      |> String.replace(~r/[\s]+/, " ")
+      |> String.trim()
+    else
+      text
+    end
   end
 
   defp node_to_text({_tag, _attrs, content}), do: node_to_text(content)

test/phoenix_live_view/integrations/elements_test.exs

@@ -618,6 +618,17 @@ defmodule Phoenix.LiveView.ElementsTest do
   end
 
   describe "submit_form" do
+    test "submits textarea with newline characters", %{live: view} do
+      view
+      |> form("#form")
+      |> render_submit()
+
+      expected_string_in_event =
+        "textarea_with_newlines\" => \"This is a test.\\nIt has multiple\\nlines of text.\""
+
+      assert last_event(view) =~ expected_string_in_event
+    end
+
     test "raises if element is not a form", %{live: view, conn: conn} do
       assert_raise ArgumentError,
                    ~r"given element did not return a form",

test/support/live_views/elements.ex

@@ -203,6 +203,7 @@ defmodule Phoenix.LiveViewTest.Support.ElementsLive do
       </select>
       <textarea name="hello[textarea]">Text</textarea>
       <textarea name="hello[textarea_empty]"></textarea>
+      <textarea name="hello[textarea_with_newlines]"><%= @multiline_text %></textarea>
       <!-- Mimic textarea from Phoenix.HTML -->
       <textarea name="hello[textarea_nl]">
     Text</textarea>
@@ -278,6 +279,7 @@ defmodule Phoenix.LiveViewTest.Support.ElementsLive do
       socket
       |> assign(:event, nil)
       |> assign(:trigger_action, false)
+      |> assign(:multiline_text, "This is a test.\nIt has multiple\nlines of text.")
 
     {:ok, socket}
   end