Bun Tanstack Start Skill for Claude

TanStack Start full-stack React framework with Bun runtime. Use for TanStack Router, server functions, vinxi, or encountering SSR, build, preset errors.

2k tokens

context cost

the whole folder, loaded on every use

files

instructions only

copies elsewhere

how many repositories repackaged it

202

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/secondsky/claude-skills --skill bun-tanstack-start

The instruction itself

23 sections, as written by the author

Bun TanStack Start

Run TanStack Start (full-stack React framework) with Bun.

Quick Start

# Create new TanStack Start project
bunx create-tanstack-start@latest my-app
cd my-app

# Install dependencies
bun install

# Development
bun run dev

# Build
bun run build

# Preview
bun run start

Secure Installation

Scaffolding tools like bunx create-tanstack-start download and execute remote code. Before running, follow supply chain security best practices:

Block post-install scripts — Bun disables them by default; allow specific packages via trustedDependencies in package.json
Cooldown period — Configure minimumReleaseAge in bunfig.toml to wait 7 days for new versions
Audit before installing — Run socket package score npm <pkg> or use socket npm install <pkg> to check packages

Load the dependency-upgrade skill for full security configuration including Socket CLI integration, cooldown setup, lockfile validation, and CI enforcement.

Project Setup

package.json

{
  "scripts": {
    "dev": "vinxi dev",
    "build": "vinxi build",
    "start": "vinxi start"
  },
  "dependencies": {
    "@tanstack/react-router": "^1.139.0",
    "@tanstack/start": "^1.120.0",
    "react": "^19.2.0",
    "react-dom": "^19.2.0",
    "vinxi": "^0.5.10"
  }
}

app.config.ts

import { defineConfig } from "@tanstack/start/config";

export default defineConfig({
  server: {
    preset: "bun",
  },
});

File-Based Routing

app/
├── routes/
│   ├── __root.tsx       # Root layout
│   ├── index.tsx        # /
│   ├── about.tsx        # /about
│   ├── users/
│   │   ├── index.tsx    # /users
│   │   └── $userId.tsx  # /users/:userId
│   └── api/
│       └── users.ts     # /api/users
└── client.tsx

Route Components

Basic Route

// app/routes/index.tsx
import { createFileRoute } from "@tanstack/react-router";

export const Route = createFileRoute("/")({
  component: Home,
});

function Home() {
  return <h1>Welcome Home</h1>;
}

Route with Loader

// app/routes/users/index.tsx
import { createFileRoute } from "@tanstack/react-router";

export const Route = createFileRoute("/users/")({
  loader: async () => {
    const response = await fetch("/api/users");
    return response.json();
  },
  component: Users,
});

function Users() {
  const users = Route.useLoaderData();

  return (
    <ul>
      {users.map((user) => (
        <li key={user.id}>{user.name}</li>
      ))}
    </ul>
  );
}

Dynamic Routes

// app/routes/users/$userId.tsx
import { createFileRoute } from "@tanstack/react-router";

export const Route = createFileRoute("/users/$userId")({
  loader: async ({ params }) => {
    const response = await fetch(`/api/users/${params.userId}`);
    return response.json();
  },
  component: UserDetail,
});

function UserDetail() {
  const user = Route.useLoaderData();
  const { userId } = Route.useParams();

  return (
    <div>
      <h1>{user.name}</h1>
      <p>User ID: {userId}</p>
    </div>
  );
}

Server Functions

Define Server Function

// app/routes/users/index.tsx
import { createFileRoute } from "@tanstack/react-router";
import { createServerFn } from "@tanstack/start";
import { Database } from "bun:sqlite";

const getUsers = createServerFn("GET", async () => {
  const db = new Database("data.sqlite");
  const users = db.query("SELECT * FROM users").all();
  db.close();
  return users;
});

const createUser = createServerFn("POST", async (name: string) => {
  const db = new Database("data.sqlite");
  db.run("INSERT INTO users (name) VALUES (?)", [name]);
  db.close();
  return { success: true };
});

export const Route = createFileRoute("/users/")({
  loader: () => getUsers(),
  component: Users,
});

function Users() {
  const users = Route.useLoaderData();

  const handleSubmit = async (e: React.FormEvent<HTMLFormElement>) => {
    e.preventDefault();
    const formData = new FormData(e.currentTarget);
    const name = formData.get("name") as string;
    await createUser(name);
    // Refetch or update state
  };

  return (
    <div>
      <form onSubmit={handleSubmit}>
        <input name="name" placeholder="Name" />
        <button type="submit">Add User</button>
      </form>
      <ul>
        {users.map((user) => (
          <li key={user.id}>{user.name}</li>
        ))}
      </ul>
    </div>
  );
}

Server Function with Context

import { createServerFn } from "@tanstack/start";
import { getWebRequest } from "@tanstack/start/server";

const getSession = createServerFn("GET", async () => {
  const request = getWebRequest();
  const cookies = request.headers.get("Cookie");
  // Parse and validate session
  return { userId: "123", role: "admin" };
});

const protectedAction = createServerFn("POST", async (data: any) => {
  const session = await getSession();

  if (session.role !== "admin") {
    throw new Error("Unauthorized");
  }

  // Perform action
  return { success: true };
});

API Routes

// app/routes/api/users.ts
import { createAPIFileRoute } from "@tanstack/start/api";
import { Database } from "bun:sqlite";

export const Route = createAPIFileRoute("/api/users")({
  GET: async ({ request }) => {
    const db = new Database("data.sqlite");
    const users = db.query("SELECT * FROM users").all();
    db.close();

    return Response.json(users);
  },

  POST: async ({ request }) => {
    const { name } = await request.json();

    const db = new Database("data.sqlite");
    db.run("INSERT INTO users (name) VALUES (?)", [name]);
    db.close();

    return Response.json({ success: true });
  },
});

Root Layout

// app/routes/__root.tsx
import { createRootRoute, Link, Outlet } from "@tanstack/react-router";

export const Route = createRootRoute({
  component: Root,
});

function Root() {
  return (
    <html>
      <head>
        <meta charSet="utf-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1" />
        <title>My App</title>
      </head>
      <body>
        <nav>
          <Link to="/">Home</Link>
          <Link to="/users">Users</Link>
          <Link to="/about">About</Link>
        </nav>
        <main>
          <Outlet />
        </main>
      </body>
    </html>
  );
}

Error Handling

// app/routes/users/$userId.tsx
export const Route = createFileRoute("/users/$userId")({
  loader: async ({ params }) => {
    const response = await fetch(`/api/users/${params.userId}`);
    if (!response.ok) {
      throw new Error("User not found");
    }
    return response.json();
  },
  errorComponent: ({ error }) => (
    <div>
      <h1>Error</h1>
      <p>{error.message}</p>
    </div>
  ),
  pendingComponent: () => <div>Loading...</div>,
  component: UserDetail,
});

Search Params

// app/routes/users/index.tsx
import { createFileRoute } from "@tanstack/react-router";
import { z } from "zod";

const searchSchema = z.object({
  page: z.number().default(1),
  limit: z.number().default(10),
  search: z.string().optional(),
});

export const Route = createFileRoute("/users/")({
  validateSearch: searchSchema,
  loader: async ({ search }) => {
    const { page, limit, search: query } = search;
    // Fetch with pagination
    return fetchUsers({ page, limit, query });
  },
  component: Users,
});

Deployment

Build for Bun

NITRO_PRESET=bun bun run build
bun .output/server/index.mjs

Docker

FROM oven/bun:1 AS builder

WORKDIR /app
COPY package.json bun.lockb ./
RUN bun install --frozen-lockfile

COPY . .
RUN bun run build

FROM oven/bun:1

WORKDIR /app
COPY --from=builder /app/.output ./output

EXPOSE 3000

CMD ["bun", ".output/server/index.mjs"]

Common Errors

| Error | Cause | Fix |

|-------|-------|-----|

| Cannot find bun:sqlite | Wrong preset | Set server.preset: "bun" |

| Server function failed | Network error | Check function definition |

| Route not found | File naming | Check route file location |

| Hydration mismatch | Server/client diff | Check loader data |

When to Load References

Load references/router-api.md when:

Advanced routing patterns
Route guards
Nested layouts

Load references/forms.md when:

Form handling
Mutations
Optimistic updates

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How to use it

Copy the folder

Take secondsky/bun-tanstack-start from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

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Install what it needs

The instructions reference npm. Without those the skill loads but fails at the first command.