/ CLAUDE.md
CLAUDE.md
1 2 Default to using Bun instead of Node.js. 3 4 - Use `bun <file>` instead of `node <file>` or `ts-node <file>` 5 - Use `bun test` instead of `jest` or `vitest` 6 - Use `bun build <file.html|file.ts|file.css>` instead of `webpack` or `esbuild` 7 - Use `bun install` instead of `npm install` or `yarn install` or `pnpm install` 8 - Use `bun run <script>` instead of `npm run <script>` or `yarn run <script>` or `pnpm run <script>` 9 - Use `bunx <package> <command>` instead of `npx <package> <command>` 10 - Bun automatically loads .env, so don't use dotenv. 11 12 ## APIs 13 14 - `Bun.serve()` supports WebSockets, HTTPS, and routes. Don't use `express`. 15 - `bun:sqlite` for SQLite. Don't use `better-sqlite3`. 16 - `Bun.redis` for Redis. Don't use `ioredis`. 17 - `Bun.sql` for Postgres. Don't use `pg` or `postgres.js`. 18 - `WebSocket` is built-in. Don't use `ws`. 19 - Prefer `Bun.file` over `node:fs`'s readFile/writeFile 20 - Bun.$`ls` instead of execa. 21 22 ## Testing 23 24 Use `bun test` to run tests. 25 26 ```ts#index.test.ts 27 import { test, expect } from "bun:test"; 28 29 test("hello world", () => { 30 expect(1).toBe(1); 31 }); 32 ``` 33 34 ## Frontend 35 36 Use HTML imports with `Bun.serve()`. Don't use `vite`. HTML imports fully support React, CSS, Tailwind. 37 38 Server: 39 40 ```ts#index.ts 41 import index from "./index.html" 42 43 Bun.serve({ 44 routes: { 45 "/": index, 46 "/api/users/:id": { 47 GET: (req) => { 48 return new Response(JSON.stringify({ id: req.params.id })); 49 }, 50 }, 51 }, 52 // optional websocket support 53 websocket: { 54 open: (ws) => { 55 ws.send("Hello, world!"); 56 }, 57 message: (ws, message) => { 58 ws.send(message); 59 }, 60 close: (ws) => { 61 // handle close 62 } 63 }, 64 development: { 65 hmr: true, 66 console: true, 67 } 68 }) 69 ``` 70 71 HTML files can import .tsx, .jsx or .js files directly and Bun's bundler will transpile & bundle automatically. `<link>` tags can point to stylesheets and Bun's CSS bundler will bundle. 72 73 ```html#index.html 74 <html> 75 <body> 76 <h1>Hello, world!</h1> 77 <script type="module" src="./frontend.tsx"></script> 78 </body> 79 </html> 80 ``` 81 82 With the following `frontend.tsx`: 83 84 ```tsx#frontend.tsx 85 import React from "react"; 86 import { createRoot } from "react-dom/client"; 87 88 // import .css files directly and it works 89 import './index.css'; 90 91 const root = createRoot(document.body); 92 93 export default function Frontend() { 94 return <h1>Hello, world!</h1>; 95 } 96 97 root.render(<Frontend />); 98 ``` 99 100 Then, run index.ts 101 102 ```sh 103 bun --hot ./index.ts 104 ``` 105 106 For more information, read the Bun API docs in `node_modules/bun-types/docs/**.mdx`.