fix(html): trim helper tokens

Co-Authored-By: Virgil <virgil@lethean.io>

node.go

@@ -355,10 +355,11 @@ func joinNonEmpty(parts ...string) string {
 
 	var filtered []string
 	for i := range parts {
-		if parts[i] == "" {
+		part := strings.TrimSpace(parts[i])
+		if part == "" {
 			continue
 		}
-		filtered = append(filtered, parts[i])
+		filtered = append(filtered, part)
 	}
 	if len(filtered) == 0 {
 		return ""

node_test.go

@@ -275,6 +275,16 @@ func TestAriaDescribedByHelper_IgnoresEmptyIDs(t *testing.T) {
 	}
 }
 
+func TestAriaDescribedByHelper_IgnoresWhitespaceIDs(t *testing.T) {
+	ctx := NewContext()
+	node := AriaDescribedBy(El("input"), " ", "hint-1", "\t", "hint-2")
+	got := node.Render(ctx)
+	want := `<input aria-describedby="hint-1 hint-2">`
+	if got != want {
+		t.Errorf("AriaDescribedBy() with whitespace IDs = %q, want %q", got, want)
+	}
+}
+
 func TestAriaLabelledByHelper(t *testing.T) {
 	ctx := NewContext()
 	node := AriaLabelledBy(El("input"), "label-1", "label-2")
@@ -452,6 +462,16 @@ func TestClassHelper_IgnoresEmptyClasses(t *testing.T) {
 	}
 }
 
+func TestClassHelper_IgnoresWhitespaceClasses(t *testing.T) {
+	ctx := NewContext()
+	node := Class(El("div", Raw("content")), " ", "card", "\t", "card--primary")
+	got := node.Render(ctx)
+	want := `<div class="card card--primary">content</div>`
+	if got != want {
+		t.Errorf("Class() with whitespace classes = %q, want %q", got, want)
+	}
+}
+
 func TestAriaHiddenHelper(t *testing.T) {
 	ctx := NewContext()