From 70320cbdeb1b3a1de84c6c3417b64141920c5e50 Mon Sep 17 00:00:00 2001
From: Paul Chavard <pro@paul.chavard.net>
Date: Fri, 17 Jan 2025 16:30:38 +0100
Subject: [PATCH] add fragment cache (to match turbo cache)

---
 packages/react/src/root.test.tsx | 28 +++++++++++++++++
 packages/react/src/root.ts       | 54 ++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+)

diff --git a/packages/react/src/root.test.tsx b/packages/react/src/root.test.tsx
index b8a23db..39e2976 100644
--- a/packages/react/src/root.test.tsx
+++ b/packages/react/src/root.test.tsx
@@ -97,6 +97,34 @@ describe('@coldwired/react', () => {
       root.destroy();
     });
 
+    it('render fragment with component and cache', async () => {
+      document.body.innerHTML = `<${DEFAULT_TAG_NAME}><${REACT_COMPONENT_TAG} ${NAME_ATTRIBUTE}="Counter"></${REACT_COMPONENT_TAG}></${DEFAULT_TAG_NAME}>`;
+      const root = createRoot({
+        loader: (name) => Promise.resolve(manifest[name]),
+        cache: true,
+      });
+      await root.render(document.body).done;
+
+      expect(document.body.innerHTML).toEqual(
+        `<${DEFAULT_TAG_NAME} data-fragment-id="fragment-0"><div><p>Count: 0</p><button>Increment</button></div></${DEFAULT_TAG_NAME}><div id="react-root"></div>`,
+      );
+
+      root.destroy();
+
+      {
+        const root = createRoot({
+          loader: (name) => Promise.resolve(manifest[name]),
+          cache: true,
+        });
+        await root.render(document.body).done;
+
+        expect(document.body.innerHTML).toEqual(
+          `<${DEFAULT_TAG_NAME} data-fragment-id="fragment-0"><div><p>Count: 0</p><button>Increment</button></div></${DEFAULT_TAG_NAME}><div id="react-root"></div>`,
+        );
+        root.destroy();
+      }
+    });
+
     it('render with error boundary', async () => {
       document.body.innerHTML = `<${DEFAULT_TAG_NAME}>
         <${REACT_COMPONENT_TAG} ${NAME_ATTRIBUTE}="Counter"></${REACT_COMPONENT_TAG}>
diff --git a/packages/react/src/root.ts b/packages/react/src/root.ts
index 520b1e9..5a85629 100644
--- a/packages/react/src/root.ts
+++ b/packages/react/src/root.ts
@@ -32,6 +32,7 @@ export interface RootOptions {
   schema?: Partial<Schema>;
   layoutComponentName?: string;
   errorBoundaryFallbackComponentName?: string;
+  cache?: boolean;
 }
 
 export interface Schema extends TreeBuilderSchema {
@@ -115,6 +116,11 @@ export function createRoot(
     }
     await preload(fragment, (names) => manifestLoader(names, loader, manifest), schema);
     const tree = hydrate(fragment, manifest, schema);
+
+    if (options.cache) {
+      saveFragmentCache(element, fragmentOrHTML);
+    }
+
     if (reset) {
       element.innerHTML = '';
     }
@@ -145,6 +151,9 @@ export function createRoot(
       await mounting;
       mounted.set(element, (fragmentOrHTML) => render(element, fragmentOrHTML, false));
       registerDestroyer(element);
+      if (options.cache) {
+        restoreFragmentCache(element);
+      }
       await render(element, element, true);
     }
   };
@@ -278,3 +287,48 @@ async function getErrorBoundaryFallbackComponent(
   }
   return;
 }
+
+let fragmentCacheIdSequence = 0;
+const fragmentCacheIdAttributeName = 'data-fragment-id';
+const fragmentCache = new Map<string, string>();
+
+export function resetFragmentCache() {
+  fragmentCache.clear();
+}
+
+function saveFragmentCache(element: Element, fragment: DocumentFragmentLike | string) {
+  let fragmentCacheId = element.getAttribute(fragmentCacheIdAttributeName);
+  if (!fragmentCacheId) {
+    fragmentCacheId = `fragment-${fragmentCacheIdSequence++}`;
+    element.setAttribute(fragmentCacheIdAttributeName, fragmentCacheId);
+  }
+  fragmentCache.set(fragmentCacheId, stringifyFragment(fragment));
+}
+
+function restoreFragmentCache(element: Element) {
+  const fragmentCacheId = element.getAttribute(fragmentCacheIdAttributeName);
+  if (fragmentCacheId) {
+    const html = fragmentCache.get(fragmentCacheId);
+    if (html) {
+      element.innerHTML = html;
+    }
+  }
+}
+
+function stringifyFragment(fragmentOrHTML: DocumentFragmentLike | string): string {
+  if (typeof fragmentOrHTML == 'string') {
+    return fragmentOrHTML;
+  }
+  if (isElement(fragmentOrHTML)) {
+    return fragmentOrHTML.innerHTML;
+  }
+  const html: string[] = [];
+  for (const node of fragmentOrHTML.childNodes) {
+    if (isElement(node)) {
+      html.push(node.outerHTML);
+    } else if (node.nodeType == Node.TEXT_NODE && node.textContent) {
+      html.push(node.textContent);
+    }
+  }
+  return html.join(' ');
+}