[eslint-config-expo] eslint config for expo projects

packages/eslint-config-expo/.eslintrc.js

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+module.exports = {
+  root: true,
+  extends: './default.js',
+  env: {
+    node: true
+  }
+};

packages/eslint-config-expo/CHANGELOG.md

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+# Changelog
+
+## Unpublished
+
+### 🛠 Breaking changes
+
+### 🎉 New features
+
+### 🐛 Bug fixes
+
+### 💡 Others

packages/eslint-config-expo/LICENSE

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+The MIT License (MIT)
+
+Copyright (c) 2016-present Expo
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/eslint-config-expo/README.md

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+# eslint-config-expo
+
+Base ESLint config for Expo projects.
+
+## Installation
+
+```sh
+yarn add --dev eslint-config-expo
+```
+
+You will also need to install `eslint`:
+
+```sh
+yarn add --dev eslint
+```
+
+## Usage
+
+Import this config into your own ESLint configuration using the `extends` option. ESLint checks both `package.json` and `.eslintrc.*` files for its configuration:
+
+### package.json
+```js
+{
+  "eslintConfig": {
+    "extends": "expo"
+  }
+}
+```
+
+### .eslintrc.js
+```js
+module.exports = {
+  extends: 'expo',
+};
+```

packages/eslint-config-expo/default.js

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+const {
+  jsExtensions,
+  tsExtensions,
+  platformSubextensions,
+  computeExpoExtensions,
+} = require('./utils/extensions');
+
+const allExtensions = computeExpoExtensions(
+  [...jsExtensions, ...tsExtensions],
+  platformSubextensions,
+);
+
+module.exports = {
+  extends: [
+    './utils/core.js',
+    './utils/typescript.js',
+    './utils/react.js',
+    './utils/expo.js',
+  ],
+  globals: {
+    __DEV__: false,
+    Atomics: false,
+    ErrorUtils: false,
+    FormData: false,
+    SharedArrayBuffer: false,
+    XMLHttpRequest: false,
+    alert: false,
+    cancelAnimationFrame: false,
+    cancelIdleCallback: false,
+    clearImmediate: false,
+    clearInterval: false,
+    clearTimeout: false,
+    fetch: false,
+    navigator: false,
+    process: false,
+    requestAnimationFrame: false,
+    requestIdleCallback: false,
+    setImmediate: false,
+    setInterval: false,
+    setTimeout: false,
+    window: false,
+  },
+  settings: {
+    'import/extensions': allExtensions,
+    'import/resolver': {
+      node: { extensions: allExtensions },
+    },
+  },
+  overrides: [
+    {
+      files: ['*.web.*'],
+      env: { browser: true },
+    },
+  ],
+};

packages/eslint-config-expo/package.json

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+{
+  "name": "eslint-config-expo",
+  "version": "7.0.0",
+  "description": "Eslint config for Expo apps",
+  "main": "default.js",
+  "scripts": {
+    "lint": "eslint ."
+  },
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/expo/expo.git",
+    "directory": "packages/eslint-config-expo"
+  },
+  "keywords": [
+    "eslint-config",
+    "expo",
+    "react-native"
+  ],
+  "files": [
+    "README.md",
+    "default.js",
+    "utils"
+  ],
+  "author": "Expo",
+  "license": "MIT",
+  "bugs": {
+    "url": "https://github.com/expo/expo/issues"
+  },
+  "homepage": "https://github.com/expo/expo/tree/main/packages/eslint-config-expo",
+  "dependencies": {
+    "@typescript-eslint/eslint-plugin": "^7.4.0",
+    "@typescript-eslint/parser": "^7.4.0",
+    "eslint": "^8.57.0",
+    "eslint-plugin-expo": "^0.0.1",
+    "eslint-plugin-import": "^2.29.1",
+    "eslint-plugin-react": "^7.34.0",
+    "eslint-plugin-react-hooks": "^4.6.0"
+  },
+  "peerDependencies": {
+    "eslint": ">=8.10"
+  }
+}

packages/eslint-config-expo/utils/core.js

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+const { jsExtensions } = require('./extensions');
+
+module.exports = {
+  parserOptions: {
+    sourceType: 'module',
+    ecmaVersion: 2022,
+    ecmaFeatures: { impliedStrict: true, jsx: true },
+  },
+  env: { es2022: true, jest: true },
+  globals: {
+    console: false,
+    exports: false,
+    global: false,
+    module: false,
+    require: false,
+  },
+  plugins: ['import', 'expo'],
+  rules: {
+    'array-bracket-spacing': ['warn', 'never'],
+    'arrow-spacing': ['warn', { before: true, after: true }],
+    curly: ['warn', 'all'],
+    'block-spacing': ['warn', 'always'],
+    'comma-dangle': ['warn', 'always-multiline'],
+    'comma-spacing': ['warn', { before: false, after: true }],
+    'comma-style': ['warn', 'last'],
+    'computed-property-spacing': ['warn', 'never'],
+    'constructor-super': 'warn',
+    'dot-location': ['warn', 'property'],
+    'eol-last': 'warn',
+    eqeqeq: ['warn', 'smart'],
+    'func-call-spacing': ['warn', 'never'],
+    'generator-star-spacing': ['warn', 'after'],
+    'getter-return': 'warn',
+    'jsx-quotes': ['warn', 'prefer-double'],
+    'new-parens': 'warn',
+    'no-alert': 'off',
+    'no-array-constructor': 'warn',
+    'no-caller': 'warn',
+    'no-case-declarations': 'warn',
+    'no-compare-neg-zero': 'warn',
+    'no-cond-assign': 'warn',
+    'no-const-assign': 'error',
+    'no-constant-condition': ['warn', { checkLoops: false }],
+    'no-control-regex': 'off',
+    'no-debugger': 'warn',
+    'no-delete-var': 'error',
+    'no-dupe-args': 'error',
+    'no-dupe-class-members': 'error',
+    'no-dupe-keys': 'error',
+    'no-duplicate-case': 'error',
+    'no-empty-character-class': 'warn',
+    'no-empty-pattern': 'warn',
+    'no-eval': 'warn',
+    'no-ex-assign': 'warn',
+    'no-extend-native': 'warn',
+    'no-extra-bind': 'warn',
+    'no-extra-boolean-cast': 'warn',
+    'no-extra-semi': 'warn',
+    'no-fallthrough': 'warn',
+    'no-floating-decimal': 'warn',
+    'no-func-assign': 'error',
+    'no-global-assign': 'warn',
+    'no-implied-eval': 'warn',
+    'no-inner-declarations': 'warn',
+    'no-invalid-regexp': 'error',
+    'no-irregular-whitespace': 'warn',
+    'no-iterator': 'warn',
+    'no-label-var': 'warn',
+    'no-labels': ['warn', { allowLoop: true, allowSwitch: true }],
+    'no-lone-blocks': 'warn',
+    'no-multi-assign': 'warn',
+    'no-new': 'warn',
+    'no-new-func': 'warn',
+    'no-new-object': 'warn',
+    'no-new-symbol': 'error',
+    'no-obj-calls': 'warn',
+    'no-octal': 'warn',
+    'no-octal-escape': 'warn',
+    'no-mixed-spaces-and-tabs': 'warn',
+    'no-proto': 'warn',
+    'no-redeclare': 'warn',
+    'no-return-assign': 'warn',
+    'no-script-url': 'warn',
+    'no-self-assign': 'warn',
+    'no-self-compare': 'warn',
+    'no-sequences': 'warn',
+    'no-shadow-restricted-names': 'warn',
+    'no-sparse-arrays': 'warn',
+    'no-this-before-super': 'warn',
+    'no-throw-literal': 'warn',
+    'no-trailing-spaces': 'warn',
+    'no-undef': 'error',
+    'no-unexpected-multiline': 'warn',
+    'no-unneeded-ternary': 'warn',
+    'no-unreachable': 'warn',
+    'no-unsafe-negation': 'warn',
+    'no-unused-expressions': ['warn', { allowShortCircuit: true, enforceForJSX: true }],
+    'no-unused-labels': 'warn',
+    'no-unused-vars': [
+      'warn',
+      {
+        vars: 'all',
+        args: 'none',
+        ignoreRestSiblings: true,
+        caughtErrors: 'all',
+        caughtErrorsIgnorePattern: '^_',
+      },
+    ],
+    'no-useless-computed-key': 'warn',
+    'no-useless-concat': 'warn',
+    'no-useless-constructor': 'warn',
+    'no-useless-escape': 'warn',
+    'no-useless-rename': 'warn',
+    'no-useless-return': 'warn',
+    'no-var': 'warn',
+    'no-void': 'warn',
+    'no-whitespace-before-property': 'warn',
+    'no-with': 'warn',
+    'object-shorthand': 'warn',
+    'operator-linebreak': ['warn', 'after', { overrides: { '?': 'before', ':': 'before' } }],
+    'prefer-const': ['warn', { destructuring: 'all', ignoreReadBeforeAssign: true }],
+    'prefer-promise-reject-errors': 'warn',
+    'prefer-rest-params': 'warn',
+    'prefer-spread': 'warn',
+    radix: 'warn',
+    'rest-spread-spacing': ['warn', 'never'],
+    semi: 'warn',
+    'semi-spacing': ['warn', { before: false, after: true }],
+    'semi-style': ['warn', 'last'],
+    'space-before-blocks': ['warn', 'always'],
+    'space-before-function-paren': ['warn', { anonymous: 'never', named: 'never' }],
+    'space-in-parens': ['warn', 'never'],
+    'space-infix-ops': 'warn',
+    'switch-colon-spacing': ['warn', { before: false, after: true }],
+    'template-curly-spacing': ['warn', 'never'],
+    'template-tag-spacing': ['warn', 'never'],
+    'unicode-bom': ['warn', 'never'],
+    'use-isnan': 'error',
+    'valid-typeof': 'error',
+    'yield-star-spacing': ['warn', 'after'],
+    yoda: ['warn', 'never', { exceptRange: true }],
+
+    'import/default': 'off',
+    'import/export': 'error',
+    'import/first': 'warn',
+    'import/namespace': ['error', { allowComputed: true }],
+    'import/no-duplicates': 'error',
+    'import/order': [
+      'warn',
+      {
+        groups: [['builtin', 'external'], 'internal', ['parent', 'index', 'sibling']],
+        'newlines-between': 'always',
+        alphabetize: {
+          order: 'asc',
+        },
+      },
+    ],
+  },
+  settings: {
+    'import/extensions': jsExtensions,
+    'import/ignore': [
+      // react-native's main module is Flow, not JavaScript, and raises parse errors. Additionally,
+      // several other react-native-related packages still publish Flow code as their main source.
+      'node_modules[\\\\/]+@?react-native',
+    ],
+    'import/resolver': {
+      node: { extensions: jsExtensions },
+    },
+  },
+  overrides: [
+    {
+      files: ['*.d.ts'],
+      rules: {
+        'import/order': 'off',
+      },
+    },
+  ],
+};

packages/eslint-config-expo/utils/expo.js

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+module.exports = {
+  plugins: ['expo'],
+  rules: {
+    "expo/no-env-var-destructuring": ["error"],
+    "expo/no-dynamic-env-var": ["error"],
+  },
+};

packages/eslint-config-expo/utils/extensions.js

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+const jsExtensions = ['.js', '.jsx'];
+const tsExtensions = ['.ts', '.tsx', '.d.ts'];
+
+const platformSubextensions = ['.android', '.ios', '.web', '.native'];
+
+function computeExpoExtensions(baseExtensions, platformSubextensions) {
+  const expoExtensions = [];
+  for (const expo of ['.expo', '']) {
+    for (const platform of [...platformSubextensions, '']) {
+      for (const base of baseExtensions) {
+        expoExtensions.push(`${expo}${platform}${base}`);
+      }
+    }
+  }
+  return expoExtensions;
+}
+
+module.exports = {
+  jsExtensions,
+  tsExtensions,
+  platformSubextensions,
+  computeExpoExtensions,
+};