feat: add keep

keep the children of the element after first render.

src/__tests__/attributes.test.ts

@@ -42,4 +42,12 @@ describe('attributes.ts', () => {
 
     expect(el.hasAttribute('mounted')).toBe(false);
   });
+
+  test("doesn't add `keep` as an attribute", () => {
+    const el = document.createElement('div');
+
+    addAttribute(el, 'keep', true);
+
+    expect(el.hasAttribute('keep')).toBe(false);
+  });
 });

src/__tests__/component.test.ts

@@ -1,7 +1,13 @@
 import { mount } from '../mount';
 import { tags } from '../tags';
 import { type Component } from '../types';
-import { getByText, getByTestId, fireEvent } from '@testing-library/dom';
+import {
+  getByText,
+  getByTestId,
+  fireEvent,
+  getByRole,
+  queryByText,
+} from '@testing-library/dom';
 
 const { div, p, button } = tags;
 
@@ -76,4 +82,34 @@ describe('components', () => {
 
     expect(el).toBeDefined();
   });
+
+  test('keep', () => {
+    const KeepComponent: Component<{ count: number }> = {
+      state: { count: 0 },
+      view({ state }) {
+        return div(
+          div(
+            [
+              `Don't change me ${state.count}`,
+              button('Increment', {
+                onclick: () => state.count++,
+              }),
+            ],
+            { keep: true },
+          ),
+        );
+      },
+    };
+
+    mount(document.body, KeepComponent);
+
+    const btn = getByRole(document.body, 'button');
+
+    expect(btn).toBeDefined();
+
+    fireEvent.click(btn);
+
+    expect(queryByText(document.body, /Don't change me 0/)).toBeTruthy();
+    expect(queryByText(document.body, /Don't change me 1/)).toBeNull();
+  });
 });

src/attributes.ts

@@ -5,7 +5,7 @@ function addAttribute<A extends Attrs>(
   key: string,
   value: TagAttrsValues,
 ) {
-  if (key === 'mounted') {
+  if (key === 'mounted' || key === 'keep') {
     return;
   }
 

src/types.ts

@@ -14,18 +14,27 @@ export type TentNode<A extends Attrs = undefined> = Node &
   Element &
   HTMLElement & {
     $tent: {
-      attributes: object;
+      attributes: Record<string, TagAttrsValues> & {
+        mounted?: ({ el }: { el: TentNode }) => void;
+        keep?: boolean;
+      };
     };
     dataset: A & DOMStringMap;
     children: TentNode<A>[];
   };
 
-export type Children = string | number | TentNode | (Node | string | Context)[];
+export type Children =
+  | string
+  | number
+  | TentNode
+  | Element
+  | (Node | string | Context)[];
 export type Context = [string, Children, TagAttrs | undefined];
 
 export type TagAttrsValues = string | boolean | number | Function;
 type TagAttrs = Record<string, TagAttrsValues> & {
   mounted?: ({ el }: { el: TentNode }) => void;
+  keep?: boolean;
 };
 export type Tags = Record<
   string,

src/walker.ts

@@ -46,6 +46,7 @@ function walker<A extends Attrs>(oldNode: TentNode<A>, newNode: TentNode<A>) {
   }
 
   if (oc.length === 0 && nc.length === 0) return;
+  if (oldNode.$tent.attributes.keep) return;
 
   if (oc.length < nc.length) {
     for (let i = 0; i < nc.length; i++) {