node manager dismount html element

pkg/app/node.go

@@ -348,7 +348,21 @@ func (m *nodeManager) Dismount(v UI) {
 }
 
 func (m *nodeManager) dismountHTML(v HTML) {
-	panic("not implemented")
+	for _, child := range v.body() {
+		m.Dismount(child)
+	}
+
+	for _, handler := range v.events() {
+		m.dismountHTMLEventHandler(handler)
+	}
+
+	v.setJSElement(nil)
+}
+
+func (m *nodeManager) dismountHTMLEventHandler(handler eventHandler) {
+	if handler.close != nil {
+		handler.close()
+	}
 }
 
 func (m *nodeManager) dismountComponent(v Composer) error {

pkg/app/node_test.go

@@ -346,6 +346,42 @@ func BenchmarkNodeManagerMount(b *testing.B) {
 	}
 }
 
+func TestNodeManagerDismount(t *testing.T) {
+	t.Run("html element is dismounted", func(t *testing.T) {
+		var m nodeManager
+
+		div, err := m.Mount(1, Div())
+		require.NoError(t, err)
+
+		m.Dismount(div)
+		require.False(t, div.Mounted())
+		require.Nil(t, div.JSValue())
+	})
+
+	t.Run("html element child is dismounted", func(t *testing.T) {
+		var m nodeManager
+
+		div, err := m.Mount(1, Div().Body(
+			Span(),
+		))
+		require.NoError(t, err)
+		span := div.(HTML).body()[0]
+
+		m.Dismount(div)
+		require.False(t, span.Mounted())
+	})
+
+	t.Run("html element event handler is dismounted", func(t *testing.T) {
+		var m nodeManager
+
+		div, err := m.Mount(1, Div().
+			On("", func(ctx Context, e Event) {}))
+		require.NoError(t, err)
+
+		m.Dismount(div)
+	})
+}
+
 func TestNodeManagerCanUpdate(t *testing.T) {
 	t.Run("elements with same type can be updated", func(t *testing.T) {
 		var m nodeManager