feat(eslint-plugin): implement ESLint plugin for Pinia best practices

packages/eslint-plugin/README.md

@@ -0,0 +1,208 @@
+# @pinia/eslint-plugin
+
+ESLint plugin for Pinia best practices and common patterns.
+
+## Installation
+
+```bash
+npm install --save-dev @pinia/eslint-plugin
+```
+
+## Usage
+
+Add `@pinia/eslint-plugin` to your ESLint configuration:
+
+### Flat Config (ESLint 9+)
+
+```js
+// eslint.config.js
+import piniaPlugin from '@pinia/eslint-plugin'
+
+export default [
+  {
+    plugins: {
+      '@pinia': piniaPlugin,
+    },
+    rules: {
+      '@pinia/require-setup-store-properties-export': 'error',
+      '@pinia/no-circular-store-dependencies': 'warn',
+      '@pinia/prefer-use-store-naming': 'warn',
+      '@pinia/no-store-in-computed': 'error',
+    },
+  },
+]
+```
+
+### Legacy Config
+
+```js
+// .eslintrc.js
+module.exports = {
+  plugins: ['@pinia'],
+  rules: {
+    '@pinia/require-setup-store-properties-export': 'error',
+    '@pinia/no-circular-store-dependencies': 'warn',
+    '@pinia/prefer-use-store-naming': 'warn',
+    '@pinia/no-store-in-computed': 'error',
+  },
+}
+```
+
+### Recommended Configuration
+
+You can use the recommended configuration which includes sensible defaults:
+
+```js
+// eslint.config.js
+import piniaPlugin from '@pinia/eslint-plugin'
+
+export default [
+  piniaPlugin.configs.recommended,
+]
+```
+
+## Rules
+
+### `@pinia/require-setup-store-properties-export`
+
+**Type:** Problem
+**Fixable:** Yes
+**Recommended:** Error
+
+Ensures that all variables and functions defined in setup stores are properly exported.
+
+According to Pinia documentation, all variables and functions defined in a setup store should be returned from the setup function to be accessible on the store instance.
+
+**❌ Incorrect:**
+```js
+export const useStore = defineStore('store', () => {
+  const count = ref(0)
+  const name = ref('test')
+
+  function increment() {
+    count.value++
+  }
+
+  // Missing exports for name and increment
+  return { count }
+})
+```
+
+**✅ Correct:**
+```js
+export const useStore = defineStore('store', () => {
+  const count = ref(0)
+  const name = ref('test')
+
+  function increment() {
+    count.value++
+  }
+
+  return { count, name, increment }
+})
+```
+
+### `@pinia/no-circular-store-dependencies`
+
+**Type:** Problem
+**Recommended:** Warning
+
+Warns about potential circular dependencies between stores and prevents store instantiation in setup function bodies.
+
+Circular dependencies can cause issues in Pinia stores, especially when stores try to access each other's state during initialization.
+
+**❌ Incorrect:**
+```js
+export const useUserStore = defineStore('user', () => {
+  // Don't instantiate stores in setup function body
+  const cartStore = useCartStore()
+  const name = ref('John')
+
+  return { name }
+})
+```
+
+**✅ Correct:**
+```js
+export const useUserStore = defineStore('user', () => {
+  const name = ref('John')
+
+  function updateProfile() {
+    // Use stores in actions
+    const cartStore = useCartStore()
+    cartStore.clear()
+  }
+
+  return { name, updateProfile }
+})
+```
+
+### `@pinia/prefer-use-store-naming`
+
+**Type:** Suggestion
+**Fixable:** Yes
+**Recommended:** Warning
+
+Enforces consistent naming conventions for Pinia stores using the "useXxxStore" pattern.
+
+**Options:**
+- `prefix` (string): Prefix for store function names (default: 'use')
+- `suffix` (string): Suffix for store function names (default: 'Store')
+
+**❌ Incorrect:**
+```js
+export const userStore = defineStore('user', () => {
+  const name = ref('John')
+  return { name }
+})
+```
+
+**✅ Correct:**
+```js
+export const useUserStore = defineStore('user', () => {
+  const name = ref('John')
+  return { name }
+})
+```
+
+### `@pinia/no-store-in-computed`
+
+**Type:** Problem
+**Recommended:** Error
+
+Prevents store instantiation inside computed properties, which can cause reactivity issues.
+
+**❌ Incorrect:**
+```js
+export default {
+  setup() {
+    const userName = computed(() => {
+      const userStore = useUserStore() // Don't instantiate here
+      return userStore.name
+    })
+
+    return { userName }
+  }
+}
+```
+
+**✅ Correct:**
+```js
+export default {
+  setup() {
+    const userStore = useUserStore() // Instantiate at top level
+
+    const userName = computed(() => userStore.name)
+
+    return { userName }
+  }
+}
+```
+
+## Contributing
+
+Contributions are welcome! Please read our contributing guidelines and submit pull requests to our GitHub repository.
+
+## License
+
+MIT

packages/eslint-plugin/package.json

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+{
+  "name": "@pinia/eslint-plugin",
+  "version": "1.0.0",
+  "description": "ESLint plugin for Pinia best practices",
+  "keywords": [
+    "vue",
+    "pinia",
+    "eslint",
+    "plugin",
+    "linting",
+    "best-practices",
+    "store"
+  ],
+  "homepage": "https://pinia.vuejs.org",
+  "bugs": {
+    "url": "https://github.com/vuejs/pinia/issues"
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/vuejs/pinia.git"
+  },
+  "funding": "https://github.com/sponsors/posva",
+  "license": "MIT",
+  "author": {
+    "name": "Eduardo San Martin Morote",
+    "email": "[email protected]"
+  },
+  "sideEffects": false,
+  "exports": {
+    "types": "./dist/index.d.ts",
+    "require": "./dist/index.js",
+    "import": "./dist/index.mjs"
+  },
+  "main": "./dist/index.js",
+  "module": "./dist/index.mjs",
+  "types": "./dist/index.d.ts",
+  "files": [
+    "dist/*.js",
+    "dist/*.mjs",
+    "dist/*.d.ts"
+  ],
+  "scripts": {
+    "build": "tsup",
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "changelog": "conventional-changelog -p angular -i CHANGELOG.md -s --commit-path . -l @pinia/eslint-plugin -r 1"
+  },
+  "devDependencies": {
+    "@typescript-eslint/parser": "^8.35.1",
+    "@typescript-eslint/rule-tester": "^8.35.1",
+    "@typescript-eslint/utils": "^8.35.1",
+    "eslint": "^9.0.0",
+    "pinia": "workspace:*",
+    "tsup": "^8.5.0",
+    "typescript": "~5.8.3",
+    "vitest": "^3.2.4"
+  },
+  "engines": {
+    "node": ">=18.18.0"
+  },
+  "peerDependencies": {
+    "eslint": ">=8.0.0"
+  },
+  "publishConfig": {
+    "access": "public"
+  }
+}

packages/eslint-plugin/src/index.ts

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+/**
+ * @fileoverview ESLint plugin for Pinia best practices
+ * @author Eduardo San Martin Morote
+ */
+
+import { requireSetupStorePropertiesExport } from './rules/require-setup-store-properties-export'
+import { noCircularStoreDependencies } from './rules/no-circular-store-dependencies'
+import { preferUseStoreNaming } from './rules/prefer-use-store-naming'
+import { noStoreInComputed } from './rules/no-store-in-computed'
+import packageJson from '../package.json'
+
+/**
+ * ESLint plugin for Pinia best practices and common patterns.
+ *
+ * This plugin provides rules to enforce best practices when using Pinia stores,
+ * including proper export patterns for setup stores, avoiding circular dependencies,
+ * and following naming conventions.
+ */
+const plugin = {
+  meta: {
+    name: '@pinia/eslint-plugin',
+    version: packageJson.version,
+  },
+  rules: {
+    'require-setup-store-properties-export': requireSetupStorePropertiesExport,
+    'no-circular-store-dependencies': noCircularStoreDependencies,
+    'prefer-use-store-naming': preferUseStoreNaming,
+    'no-store-in-computed': noStoreInComputed,
+  },
+}
+
+// Flat config export
+;(plugin as any).configs = {
+  recommended: [
+    {
+      plugins: { '@pinia': plugin as any },
+      rules: {
+        '@pinia/require-setup-store-properties-export': 'error',
+        '@pinia/no-circular-store-dependencies': 'warn',
+        '@pinia/prefer-use-store-naming': 'warn',
+        '@pinia/no-store-in-computed': 'error',
+      },
+    },
+  ],
+}
+
+export default plugin