feat: add antfu/skills

Author: pany-ang

.agents/skills/antfu/SKILL.md

@@ -0,0 +1,144 @@
+---
+name: antfu
+description: Anthony Fu's opinionated tooling and conventions for JavaScript/TypeScript projects. Use when setting up new projects, configuring ESLint/Prettier alternatives, monorepos, library publishing, or when the user mentions Anthony Fu's preferences.
+metadata:
+  author: Anthony Fu
+  version: "2026.05.01"
+---
+
+## Coding Practices
+
+### Code Organization
+
+- **Single responsibility**: Each source file should have a clear, focused scope/purpose
+- **Split large files**: Break files when they become large or handle too many concerns
+- **Type separation**: Always separate types and interfaces into `types.ts` or `types/*.ts`
+- **Constants extraction**: Move constants to a dedicated `constants.ts` file
+
+### Runtime Environment
+
+- **Prefer isomorphic code**: Write runtime-agnostic code that works in Node, browser, and workers whenever possible
+- **Clear runtime indicators**: When code is environment-specific, add a comment at the top of the file:
+
+```ts
+// @env node
+// @env browser
+```
+
+### TypeScript
+
+- **Explicit return types**: Declare return types explicitly when possible
+- **Avoid complex inline types**: Extract complex types into dedicated `type` or `interface` declarations
+
+### Comments
+
+- **Avoid unnecessary comments**: Code should be self-explanatory
+- **Explain "why" not "how"**: Comments should describe the reasoning or intent, not what the code does
+
+### Testing (Vitest)
+
+- Test files: `foo.ts` → `foo.test.ts` (same directory)
+- Use `describe`/`it` API (not `test`)
+- Use `toMatchSnapshot` for complex outputs
+- Use `toMatchFileSnapshot` with explicit path for language-specific snapshots
+
+---
+
+## Tooling Choices
+
+### @antfu/ni Commands
+
+| Command | Description |
+|---------|-------------|
+| `ni` | Install dependencies |
+| `ni <pkg>` / `ni -D <pkg>` | Add dependency / dev dependency |
+| `nr <script>` | Run script |
+| `nu` | Upgrade dependencies |
+| `nun <pkg>` | Uninstall dependency |
+| `nci` | Clean install (`pnpm i --frozen-lockfile`) |
+| `nlx <pkg>` | Execute package (`npx`) |
+
+### Checking npm Package Versions
+
+Use [`fast-npm-meta`](https://github.com/antfu/fast-npm-meta) to look up the latest version of a package — it queries a small metadata endpoint instead of downloading the full registry payload (which can be megabytes per package).
+
+```bash
+nlx fast-npm-meta version vite              # 7.3.1
+nlx fast-npm-meta version "nuxt@^3.5"       # 3.5.22 — range-aware
+nlx fast-npm-meta version vite nuxt vue     # multiple at once
+nlx fast-npm-meta version vite --json       # JSON for scripting
+nlx fast-npm-meta full vite                 # full version list + dist-tags
+```
+
+Prefer this over `npm view <pkg> version` when you only need the latest version, and over reading `package.json` from the registry directly.
+
+### TypeScript Config
+
+```json
+{
+  "compilerOptions": {
+    "target": "ESNext",
+    "module": "ESNext",
+    "moduleResolution": "bundler",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "noEmit": true
+  }
+}
+```
+
+### ESLint Setup
+
+```js
+// eslint.config.mjs
+import antfu from '@antfu/eslint-config'
+
+export default antfu()
+```
+
+
+When completing tasks, run `pnpm run lint --fix` to format the code and fix coding style.
+
+For detailed configuration options: [antfu-eslint-config](references/antfu-eslint-config.md)
+
+### Git Hooks
+
+```json
+{
+  "simple-git-hooks": {
+    "pre-commit": "pnpm i --frozen-lockfile --ignore-scripts --offline && npx lint-staged"
+  },
+  "lint-staged": { "*": "eslint --fix" },
+  "scripts": {
+    "prepare": "npx simple-git-hooks"
+  }
+}
+```
+
+### pnpm Catalogs
+
+Use named catalogs in `pnpm-workspace.yaml` for version management:
+
+| Catalog | Purpose |
+|---------|---------|
+| `prod` | Production dependencies |
+| `inlined` | Bundler-inlined dependencies |
+| `dev` | Dev tools (linter, bundler, testing) |
+| `frontend` | Frontend libraries |
+
+Avoid the default catalog. Catalog names can be adjusted per project needs.
+
+---
+
+## References
+
+| Topic | Description | Reference |
+|-------|-------------|-----------|
+| ESLint Config | Framework support, formatters, rule overrides, VS Code settings | [antfu-eslint-config](references/antfu-eslint-config.md) |
+| Project Setup | .gitignore, GitHub Actions, VS Code extensions | [setting-up](references/setting-up.md) |
+| App Development | Vue/Nuxt/UnoCSS conventions and patterns | [app-development](references/app-development.md) |
+| Library Development | tsdown bundling, pure ESM publishing | [library-development](references/library-development.md) |
+| Monorepo | pnpm workspaces, centralized alias, Turborepo | [monorepo](references/monorepo.md) |