@theguild/eslint-config/src/base.js

The Guild's shared ESLint config

const { RESTRICTED_SYNTAX, RESTRICTED_GLOBALS, RESTRICTED_MODULES } = require('./constants.js');

/** @type {import('eslint').Linter.Config} */
module.exports = {
  extends: ['eslint:recommended', 'plugin:@typescript-eslint/recommended', 'prettier'],
  plugins: ['sonarjs', 'unicorn', 'promise', 'import', 'n'],
  rules: {
    // Disallows if statements as the only statement in else blocks
    // https://eslint.org/docs/rules/no-lonely-if
    'no-lonely-if': 'error',
    // Disallows the use of console
    // https://eslint.org/docs/rules/no-console
    'no-console': 'error',
    // Requires method and property shorthand syntax for object literals
    // https://eslint.org/docs/rules/object-shorthand
    'object-shorthand': ['error', 'always'],
    // Disallows loops with a body that allows only one iteration
    // https://eslint.org/docs/rules/no-unreachable-loop
    'no-unreachable-loop': 'error',
    'sonarjs/no-one-iteration-loop': 'off', // similar to 'no-unreachable-loop' but reports less cases
    'prefer-arrow-callback': ['error', { allowNamedFunctions: true }],

    'sonarjs/no-unused-collection': 'error',
    'sonarjs/no-identical-conditions': 'error',
    'sonarjs/no-inverted-boolean-check': 'error',
    'sonarjs/no-use-of-empty-return-value': 'error',
    'sonarjs/no-gratuitous-expressions': 'error',
    'sonarjs/no-nested-switch': 'error',
    'unicorn/no-lonely-if': 'error',
    'sonarjs/no-collapsible-if': 'off', // same as 'unicorn/no-lonely-if'
    'unicorn/no-array-push-push': 'error',
    'unicorn/no-instanceof-array': 'error',
    'unicorn/no-empty-file': 'error',
    'unicorn/no-useless-fallback-in-spread': 'error',
    'unicorn/prefer-array-find': 'error',
    'unicorn/no-useless-spread': 'error',
    'unicorn/prefer-includes': 'error',

    // Disallows specified syntax
    // https://eslint.org/docs/rules/no-restricted-syntax
    'no-restricted-syntax': ['error', ...RESTRICTED_SYNTAX],
    'no-else-return': ['error', { allowElseIf: false }],
    'promise/no-nesting': 'error',

    'import/extensions': ['error', 'ignorePackages'], // Bob when bundling requires to have `.js` extension
    'import/no-default-export': 'error',
    'import/prefer-default-export': 'off', // disable opposite of 'import/no-default-export'
    'unicorn/filename-case': 'error',

    '@typescript-eslint/no-unused-vars': [
      'error',
      {
        argsIgnorePattern: '^_',
        varsIgnorePattern: '^_', // allow underscores in destructuring
      },
    ],

    // Enforce the style of numeric separators by correctly grouping digits
    // https://github.com/sindresorhus/eslint-plugin-unicorn/blob/main/docs/rules/numeric-separators-style.md
    'unicorn/numeric-separators-style': 'error',
    // Prefer using the node: protocol when importing Node.js builtin modules
    // https://github.com/sindresorhus/eslint-plugin-unicorn/blob/main/docs/rules/prefer-node-protocol.md
    'unicorn/prefer-node-protocol': 'error',
    // Reports any imports that come after non-import statements
    // https://github.com/import-js/eslint-plugin-import/blob/main/docs/rules/first.md
    'import/first': 'error',
    // Disallow shorthand type conversions
    // https://eslint.org/docs/latest/rules/no-implicit-coercion
    'no-implicit-coercion': [
      'error',
      {
        disallowTemplateShorthand: true,
        // in TypeScript `!!` is preferable https://www.typescriptlang.org/docs/handbook/2/narrowing.html#truthiness-narrowing
        boolean: false,
      },
    ],
    // Disallow specified modules when loaded by `import` declarations
    // https://github.com/eslint-community/eslint-plugin-n/blob/master/docs/rules/no-restricted-import.md
    'n/no-restricted-import': ['error', RESTRICTED_MODULES],
    // Disallow specified modules when loaded by require
    // https://github.com/eslint-community/eslint-plugin-n/blob/master/docs/rules/no-restricted-require.md
    'n/no-restricted-require': ['error', RESTRICTED_MODULES],
    'no-restricted-modules': 'off', // deprecated in favor of corresponding rules from `eslint-plugin-n`

    // Disallow specified global variables
    // https://eslint.org/docs/latest/rules/no-restricted-globals
    'no-restricted-globals': ['error', ...RESTRICTED_GLOBALS],

    '@typescript-eslint/no-explicit-any': 'error',
    'prefer-const': ['error', { destructuring: 'all' }],

    'import/no-duplicates': 'error',
    'import/newline-after-import': 'off', // prettified by prettier-plugin-sort-imports

    'prefer-object-has-own': 'error',
    'logical-assignment-operators': ['error', 'always', { enforceForIfStatements: true }],

    yoda: 'error',
    'unicorn/prefer-export-from': ['error', { ignoreUsedVariables: true }],
    'promise/no-multiple-resolved': 'error',
    'unicorn/prefer-logical-operator-over-ternary': 'error',
    'no-unused-expressions': 'off',
    '@typescript-eslint/no-unused-expressions': 'error',
    'no-negated-condition': 'off',
    'unicorn/no-negated-condition': 'error', // has autofix

    'unicorn/no-array-for-each': 'error',
    'unicorn/prefer-string-trim-start-end': 'error',
    'no-self-compare': 'error',
    eqeqeq: ['error', 'always', { null: 'ignore' }],

    'import/no-useless-path-segments': 'error',

    // 'prefer-destructuring': [ // TODO: Rediscuss later
    //   'error',
    //   {
    //     VariableDeclarator: { array: false, object: true },
    //     AssignmentExpression: { array: true, object: false },
    //   },
    //   { enforceForRenamedProperties: false },
    // ],

    'require-await': 'off',
    // Disallow async functions which have no await expression
    // https://typescript-eslint.io/rules/require-await/
    // '@typescript-eslint/require-await': 'error', // TODO: enable

    'no-return-await': 'off',
    // Enforce consistent returning of awaited values.
    // https://typescript-eslint.io/rules/return-await/
    // '@typescript-eslint/return-await': 'error', // TODO: enable
  },
};