`, favicon, and body of `Root()` to\nmatch your app's existing `index.html`, and stamp anything else your shell\nreferences directly (images, css) with `immutableFileUrl()`.\n\n1. Create `frontend/root.tsx`:\n\n```tsx\n/** @jsxImportSource npm:hono@4/jsx */\nimport { raw } from \"npm:hono@4/html\";\nimport { immutableFileUrl } from \"https://esm.town/v/std/utils/index.ts\";\n\n// The HTML shell for the app. It is never cached, so immutableFileUrl can stamp\n// the current val version into each asset URL — the browser caches those\n// immutably, and publishing the val changes the URLs, refetching exactly once.\nexport function Root() {\n return (\n <>\n {raw(\"<!DOCTYPE html>\")}\n <html lang=\"en\">\n <head>\n <meta charSet=\"UTF-8\" />\n <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\" />\n <title>React Hono Val Town Starter

[{"_1":2,"_3":-5,"_4":-5},"loaderData",{"_5":6,"_7":8,"_9":10},"actionData","errors","root",{"_280":281,"_282":283},"routes/_app.x.$handle.$name",{"_99":98,"_32":45,"_108":89,"_27":109,"_13":14,"_110":-5,"_11":111,"_112":113,"_114":115,"_116":117,"_118":119,"_20":-5,"_120":-5,"_121":-5,"_122":25,"_123":124,"_125":58,"_126":-5,"_127":-5,"_128":129},"routes/_app.x.$handle.$name.branch.$branch.version.$version.diff",{"_11":12,"_13":14,"_15":16,"_17":-5,"_18":-5},"project",{"_43":44,"_32":45,"_38":46,"_47":-5,"_48":25,"_49":50,"_51":50,"_52":53,"_54":-5,"_18":55,"_56":31,"_57":58,"_59":-5,"_60":-5,"_61":62,"_63":64,"_65":66,"_67":68,"_69":70,"_71":-5,"_72":73,"_74":73,"_75":76,"_77":76,"_78":76,"_79":73,"_80":73,"_81":82,"_83":84,"_85":86,"_87":25},"version",136,"changes",[19],"aiChatInfo","userId",{"_20":21,"_22":23,"_24":25,"_26":25,"_27":28,"_29":28},"file",{"_30":31,"_32":28,"_33":34,"_35":37,"_38":39,"_40":14,"_41":42,"_24":25},"previous",{"_30":31,"_32":28,"_33":34,"_35":36},"deleted",false,"deletedHere","path","index.ts","latestPath","fileId","01a04b7f-e043-776f-9b1e-67170ce79a7b","name","fileType","http","content","import { parseVal, serveImmutableFile, listFiles } from \"https://esm.town/v/std/utils/index.ts\";\nimport { Hono } from \"npm:hono\";\nimport { Root } from \"./frontend/root.tsx\";\n\nconst app = new Hono();\n\napp.get(\"/\", (c) => c.html(Root()));\napp.get(\"/sw.js\", async (c) => {\\n const files = await listFiles(import.meta.url);\\n const version = String(files.find((file) => file.path === \"/frontend/index.tsx\")?.version ?? Date.now());\\n const script = `const VERSION = ${JSON.stringify(version)};\\nconst CACHE = \"polyatomics-v\" + VERSION;\\nconst SHELL = [\"/\"];\\nlet hadPreviousCache = false;\\nself.addEventListener(\"install\", (event) => { event.waitUntil(caches.keys().then((keys) => { hadPreviousCache = keys.some((key) => key.startsWith(\"polyatomics-v\")); return caches.open(CACHE); }).then((cache) => cache.addAll(SHELL)).then(() => self.skipWaiting())); });\\nself.addEventListener(\"activate\", (event) => { event.waitUntil(caches.keys().then((keys) => Promise.all(keys.filter((key) => key.startsWith(\"polyatomics-v\") && key !== CACHE).map((key) => caches.delete(key)))).then(() => self.clients.claim()).then(() => hadPreviousCache ? self.clients.matchAll({ type: \"window\", includeUncontrolled: true }).then((clients) => clients.forEach((client) => client.postMessage({ type: \"UPDATE_AVAILABLE\", version: VERSION }))) : undefined)); });\\nself.addEventListener(\"fetch\", (event) => { const request = event.request; if (request.method !== \"GET\") return; event.respondWith(caches.match(request).then((cached) => cached || fetch(request).then((response) => { if (response.ok || response.type === \"opaque\") { const copy = response.clone(); caches.open(CACHE).then((cache) => cache.put(request, copy)); } return response; }).catch(() => request.mode === \"navigate\" ? caches.match(\"/\") : new Response(\"Offline\", { status: 503, statusText: \"Offline\" })))); });`;\\n return c.body(script, 200, { \"Content-Type\": \"application/javascript; charset=UTF-8\", \"Cache-Control\": \"no-cache\" });\\n});\napp.get(\"/__immutable/*\", (c) => serveImmutableFile(c.req.path));\napp.get(\"/source\", (c) => c.redirect(parseVal().links.self.val));\napp.onError((err) => Promise.reject(err));\n\nexport default app.fetch;\n","import { parseVal, serveImmutableFile, listFiles } from \"https://esm.town/v/std/utils/index.ts\";\nimport { Hono } from \"npm:hono\";\nimport { Root } from \"./frontend/root.tsx\";\n\nconst app = new Hono();\n\napp.get(\"/\", (c) => c.html(Root()));\napp.get(\"/sw.js\", async (c) => {\\n const files = await listFiles(import.meta.url);\\n const version = String(files.find((file) => file.path === \"/frontend/index.tsx\" || file.path === \"frontend/index.tsx\")?.version ?? Date.now());\\n const script = `const VERSION = ${JSON.stringify(version)};\\nconst CACHE = \"polyatomics-v\" + VERSION;\\nconst SHELL = [\"/\"];\\nlet hadPreviousCache = false;\\nself.addEventListener(\"install\", (event) => { event.waitUntil(caches.keys().then((keys) => { hadPreviousCache = keys.some((key) => key.startsWith(\"polyatomics-v\")); return caches.open(CACHE); }).then((cache) => cache.addAll(SHELL)).then(() => self.skipWaiting())); });\\nself.addEventListener(\"activate\", (event) => { event.waitUntil(caches.keys().then((keys) => Promise.all(keys.filter((key) => key.startsWith(\"polyatomics-v\") && key !== CACHE).map((key) => caches.delete(key)))).then(() => self.clients.claim()).then(() => hadPreviousCache ? self.clients.matchAll({ type: \"window\", includeUncontrolled: true }).then((clients) => clients.forEach((client) => client.postMessage({ type: \"UPDATE_AVAILABLE\", version: VERSION }))) : undefined)); });\\nself.addEventListener(\"fetch\", (event) => { const request = event.request; if (request.method !== \"GET\") return; event.respondWith(caches.match(request).then((cached) => cached || fetch(request).then((response) => { if (response.ok || response.type === \"opaque\") { const copy = response.clone(); caches.open(CACHE).then((cache) => cache.put(request, copy)); } return response; }).catch(() => request.mode === \"navigate\" ? caches.match(\"/\") : new Response(\"Offline\", { status: 503, statusText: \"Offline\" })))); });`;\\n return c.body(script, 200, { \"Content-Type\": \"application/javascript; charset=UTF-8\", \"Cache-Control\": \"no-cache\" });\\n});\napp.get(\"/__immutable/*\", (c) => serveImmutableFile(c.req.path));\napp.get(\"/source\", (c) => c.redirect(parseVal().links.self.val));\napp.onError((err) => Promise.reject(err));\n\nexport default app.fetch;\n","createdAt",["D",1787984758864],"branchVersion","branchId","91efcfc2-57fc-4e40-a802-a0a982202b7c","id","b7e65ae6-0a45-4ddf-9a18-259d42abc50b","polyatomics",["D",1787973066715],"deletedAt","legacyEnvVars","privacy","public","httpPrivacy","description","Practice polyatomic ion formulas and charges","imageUrl","a0dbc0e3-e526-4d2e-b19c-fcb458a27a4e","pinnedFileId","pinPreview",true,"pinMigrated","screenshotVersion","likeCount",0,"orgId","01a04933-e278-70de-a7be-b64137dd639b","tursoName","b7e65ae60a454ddf9a18259d42abc50b","tursoHostname","b7e65ae60a454ddf9a18259d42abc50b-val-town.aws-us-east-2.turso.io","tursoMeasuredAt",["D",1789448471428],"pinned","userPerm","r","valPerm","blobPerm","rw","emailPerm","sqlitePerm","projectPerm","telemetryPerm","user",{"_99":98,"_107":103},"org",{"_99":98,"_100":101,"_102":103,"_18":55,"_104":105,"_106":25},"branch",{"_13":88,"_32":89,"_43":42,"_90":44,"_91":-5,"_92":-5,"_93":-5,"_94":-5,"_95":-5,"_96":45,"_97":98},"isOwned",242,"main","projectId","forkedBranchId","forkedBranchVersion","forkedProjectPrivacy","forkedProjectId","forkedProjectOrgId","projectName","userHandle","altors_graphika","handle","displayName","Altors-Graphika","avatar","https://imagedelivery.net/iHX6Ovru0O7AjmyT5yZRoA/d88c49d9-df42-4251-2a99-48ca93b86e01/square512?exp=1789541999&sig=a030c50c041a86e66893f789c87907c37440f6c7f6b990388333b36b3fb7b934","tier","free","canRestrictVals","profileImageUrl","branchName","","adoptOrgId",{"_43":44,"_32":45,"_38":275,"_47":-5,"_48":25,"_49":50,"_51":50,"_52":53,"_54":-5,"_18":55,"_56":31,"_57":58,"_59":-5,"_60":-5,"_61":62,"_63":64,"_65":66,"_67":68,"_69":276,"_71":-5,"_72":73,"_74":73,"_75":76,"_77":76,"_78":76,"_79":73,"_80":73,"_81":277,"_83":278,"_85":279,"_87":25},"tree",[170,181,182,183],"files",[170,171,172,173,174,175,176,177,178,179,180,181,182,183],"counts",{"_160":62,"_161":144,"_162":62,"_163":164,"_165":166},"contents",[130,131,132,133],"upstreamProject","upstreamBranch","emptyEnvVars","flags",[],"hasHttpFiles","grants","orgs","customDomains",{},{"_43":154,"_32":155,"_30":156,"_135":-5,"_41":42,"_40":144,"_136":58,"_38":157,"_13":62,"_33":158,"_35":-5,"_24":25,"_139":-5,"_27":159},{"_43":148,"_32":149,"_30":150,"_135":-5,"_41":42,"_40":144,"_136":25,"_38":151,"_13":62,"_33":20,"_35":152,"_24":25,"_139":-5,"_27":153},{"_43":141,"_32":142,"_30":143,"_135":-5,"_41":42,"_40":144,"_136":25,"_38":145,"_13":62,"_33":20,"_35":146,"_24":25,"_139":-5,"_27":147},{"_43":134,"_32":28,"_30":31,"_135":-5,"_41":42,"_40":14,"_136":25,"_38":137,"_13":138,"_33":34,"_35":37,"_24":25,"_139":45,"_27":140},"42a08404-73aa-40e4-b4fe-c0b21aefee28","parentId","latest",["D",1787984758864],6,"label",[28],"ddc42079-4ac9-4955-8cba-fc0870e3ce3c","README.md","01a04b7f-e043-776f-9b1e-61c237442125",1,["D",1787973066715],"# React + Hono Starter\n\nA minimal starter template for building client-side React apps with a Hono\nbackend on Val Town. Click **Remix** to get your own copy.\n\n## Picking a starter\n\n| Starter | When to pick it |\n| --- | --- |\n| [`basic-html-starter`](https://www.val.town/x/templates/basic-html-starter) | Static HTML pages. Sprinkle of vanilla JS. No server-side rendering. |\n| [`hono-jsx-starter`](https://www.val.town/x/templates/hono-jsx-starter) | Dynamic server-rendered HTML with JSX. API routes. No React, no SPA. |\n| **[`react-hono-starter`](https://www.val.town/x/templates/react-hono-starter)** *(you're here)* | Client-side React SPA with a Hono API backend. |\n\n**Want to build UI?** Start writing React components in\n[`frontend/components/`](/frontend/components/). Import them into `App.tsx` and\nyou're good to go. Styling is [Twind](https://twind.style/) — just use Tailwind\nutility classes, zero config.\n\n**Want to add an API?** Add routes in [`index.ts`](/index.ts) (there's a\ncommented-out example). Fetch them from your React components.\n\n## Architecture\n\n```mermaid\ngraph LR\n Browser -->|\"GET /\"| Hono[\"index.ts
(Hono server)\"]\n Hono -->|serves| HTML[\"root.tsx\"]\n HTML -->|loads| Entry[\"index.tsx\"]\n Entry -->|renders| App[\"App.tsx\"]\n App -->|renders| Counter[\"Counter.tsx\"]\n```\n\n## File structure\n\n```\nindex.ts ← Hono backend (serves frontend + API routes)\nfrontend/\n root.tsx ← HTML shell (stamps immutable asset URLs)\n index.tsx ← React entrypoint (mounts )\n favicon.svg ← App icon\n components/\n App.tsx ← Root component (layout + view source link)\n Counter.tsx ← Example component with state\n```\n\n## How it works\n\n1. **`index.ts`** is the HTTP entrypoint — a Hono server that serves the\n frontend and any API routes you add.\n2. **`frontend/root.tsx`** is the HTML shell — it loads Twind and stamps\n immutable asset URLs for the favicon and React entrypoint.\n3. **`frontend/index.tsx`** mounts the React app.\n4. **`frontend/components/App.tsx`** is the root layout — add new components\n alongside it.\n5. **`frontend/components/Counter.tsx`** is an example stateful component —\n replace it with your own!\n\n## Next steps\n\n- Add API routes in `index.ts`\n- Add new components in `frontend/components/`\n- Add a SQLite database — see the\n [React Hono Example](https://www.val.town/x/stevekrouse/reactHonoExample) for\n a full-stack example with database, queries, and shared types\n\nTemplate updates and upgrade paths for existing remixes: [CHANGELOG.md](/CHANGELOG.md)\n",[142],"2f8efb19-122b-4b2a-87f5-04cb543486ff","CHANGELOG.md","01a04b7f-e043-776f-9b1e-5cae9d820f79",["D",1787973066715],"# Changelog\n\n## 2026-07-30 — Immutable asset caching\n\nFrontend files are now served at version-addressed URLs\n(`/__immutable/45/frontend/index.tsx`) with\n`Cache-Control: public, max-age=31536000, immutable`, so repeat visits load the\nwhole client graph from the browser cache — roughly 3× faster (~665ms → ~157ms\nmeasured). Publishing your val bumps its version, which changes every URL, so\ncaches invalidate automatically. Old-version URLs return 404 after a publish\n(like Next.js build assets); a reload picks up the new version.\n\nWhat changed in the template:\n\n- `frontend/index.html` → [`frontend/root.tsx`](/frontend/root.tsx): the HTML\n shell is now JSX and stamps asset URLs with `immutableFileUrl()`\n- [`index.ts`](/index.ts): serves `Root()` at `/`, and one\n `app.get(\"/__immutable/*\", (c) => serveImmutableFile(c.req.path))` route\n serves all frontend files\n\n### Upgrading an existing remix\n\nYour copy of this template doesn't update automatically. Two options:\n\n**Minimal (most of the benefit):** point both routes at `serveImmutableFile` —\nyour existing bare URLs redirect into versioned space, the new route serves\nthem, and the whole module graph gets cached (costs one redirect per page view):\n\n```ts\nimport { serveImmutableFile } from \"https://esm.town/v/std/utils/index.ts\";\n\napp.get(\"/__immutable/*\", (c) => serveImmutableFile(c.req.path));\napp.get(\"/frontend/**/*\", (c) => serveImmutableFile(c.req.path)); // was serveFile\n```\n\n**Full upgrade (also removes the redirect):** three self-contained steps —\nno other files needed. Adjust the ``, favicon, and body of `Root()` to\nmatch your app's existing `index.html`, and stamp anything else your shell\nreferences directly (images, css) with `immutableFileUrl()`.\n\n1. Create `frontend/root.tsx`:\n\n```tsx\n/** @jsxImportSource npm:hono@4/jsx */\nimport { raw } from \"npm:hono@4/html\";\nimport { immutableFileUrl } from \"https://esm.town/v/std/utils/index.ts\";\n\n// The HTML shell for the app. It is never cached, so immutableFileUrl can stamp\n// the current val version into each asset URL — the browser caches those\n// immutably, and publishing the val changes the URLs, refetching exactly once.\nexport function Root() {\n return (\n <>\n {raw(\"<!DOCTYPE html>\")}\n <html lang=\"en\">\n <head>\n <meta charSet=\"UTF-8\" />\n <meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\" />\n <title>React Hono Val Town Starter\n

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