Add RenderableGroup to render a group of nodes without a parent element

internal/web/component/renderable_group.go

@@ -0,0 +1,26 @@
+package component
+
+import (
+	"bytes"
+
+	"github.com/maragudk/gomponents"
+)
+
+// RenderableGroup renders a group of nodes without a parent element.
+//
+// This is because gomponents.Group() cannot be directly rendered and
+// needs to be wrapped in a parent element.
+func RenderableGroup(children []gomponents.Node) gomponents.Node {
+	if len(children) == 0 {
+		return gomponents.Raw("")
+	}
+
+	buf := bytes.Buffer{}
+	for _, child := range children {
+		err := child.Render(&buf)
+		if err != nil {
+			return gomponents.Raw("Error rendering group")
+		}
+	}
+	return gomponents.Raw(buf.String())
+}

internal/web/component/renderable_group_test.go

@@ -0,0 +1,70 @@
+package component
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/maragudk/gomponents"
+	"github.com/maragudk/gomponents/html"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestRenderableGroupRenderer(t *testing.T) {
+	t.Run("renders a group of string nodes without a parent element", func(t *testing.T) {
+		gotRenderer := RenderableGroup([]gomponents.Node{
+			gomponents.Text("foo"),
+			gomponents.Text("bar"),
+		})
+
+		got := bytes.Buffer{}
+		err := gotRenderer.Render(&got)
+		assert.NoError(t, err)
+
+		expected := "foobar"
+
+		assert.Equal(t, expected, got.String())
+	})
+
+	t.Run("renders a group of tag nodes without a parent element", func(t *testing.T) {
+		gotRenderer := RenderableGroup([]gomponents.Node{
+			html.Span(
+				gomponents.Text("foo"),
+			),
+			html.P(
+				gomponents.Text("bar"),
+			),
+		})
+
+		got := bytes.Buffer{}
+		err := gotRenderer.Render(&got)
+		assert.NoError(t, err)
+
+		expected := `<span>foo</span><p>bar</p>`
+
+		assert.Equal(t, expected, got.String())
+	})
+
+	t.Run("empty group", func(t *testing.T) {
+		gotRenderer := RenderableGroup([]gomponents.Node{})
+
+		got := bytes.Buffer{}
+		err := gotRenderer.Render(&got)
+		assert.NoError(t, err)
+
+		expected := ``
+
+		assert.Equal(t, expected, got.String())
+	})
+
+	t.Run("nil group", func(t *testing.T) {
+		gotRenderer := RenderableGroup(nil)
+
+		got := bytes.Buffer{}
+		err := gotRenderer.Render(&got)
+		assert.NoError(t, err)
+
+		expected := ``
+
+		assert.Equal(t, expected, got.String())
+	})
+}