eslint.config.js

import stylisticJs from '@stylistic/eslint-plugin-js';

import globals from 'globals';

import js from "@eslint/js"

export default [
  js.configs.recommended,
  {
    languageOptions: {
       ecmaVersion: 'latest',
       sourceType: 'module',
       globals: {
         ...globals.browser,
         ...globals.node,
         MathJax: 'readonly'
    }
    },
    plugins: {
      '@stylistic/js': stylisticJs
    },
    rules: {
        'array-callback-return': 'error',
        'consistent-return': 'off',
        camelcase: 'off',
        'default-case-last': 'error',
        eqeqeq: 'warn',
        curly: ['warn', 'multi-or-nest'],
        'one-var': ['warn', 'consecutive'],
        'no-new-func': 'off',
        'no-unused-vars': 'error',
        'no-use-before-define': ['error', {
           functions: true,
           classes: true,
           variables: true,
           allowNamedExports: false
        }],
        'no-unreachable-loop': 'error',
        'no-unreachable': 'error',
        'no-constant-condition': 'error',
        'no-unmodified-loop-condition': 'error',
        'no-else-return': 'warn',
        'no-extra-bind': 'error',
        'no-extra-boolean-cast': 'warn',
        'no-implicit-coercion': 'warn',
        'for-direction': 'error',
        'no-undef': 'warn',
        'no-await-in-loop': 'warn',
        'no-class-assign': 'error',
        'no-cond-assign': 'warn',
        'no-constructor-return': 'error',
        'no-duplicate-imports': 'error',
        'no-promise-executor-return': 'error',
        'no-self-compare': 'error',
        'no-template-curly-in-string': 'warn',
        'no-useless-assignment': 'warn',
        'no-implicit-globals': 'warn',
        'no-invalid-this': 'off',
        'no-labels': 'error',
        'no-lonely-if': 'warn',
        'no-return-assign': 'warn',
        'no-shadow': 'warn',
        'no-throw-literal': 'warn',
        'no-unneeded-ternary': 'warn',
        'no-unused-expressions': 'warn',
        'no-useless-call': 'warn',
        'no-useless-computed-key': 'warn',
        'no-useless-constructor': 'warn',
        'no-useless-rename': 'warn',
        'no-useless-return': 'warn',
        'no-var': 'error',
        'no-void': 'error',
        'object-shorthand': 'warn',
        'operator-assignment': ['warn', 'always'],
        'prefer-arrow-callback': 'warn',
        'prefer-const': 'warn',
        'prefer-numeric-literals': 'warn',
        'prefer-object-has-own': 'warn',
        'prefer-promise-reject-errors': 'warn',
        'prefer-rest-params': 'warn',
        'prefer-spread': 'warn',
        'prefer-template': 'off',

        // moved to @stylistic/js
        '@stylistic/js/semi': 'warn',
        '@stylistic/js/quotes': ['warn', 'single'],
        '@stylistic/js/indent': 'off',
        '@stylistic/js/array-bracket-spacing': 'warn',
        '@stylistic/js/comma-spacing': 'warn',
        '@stylistic/js/keyword-spacing': 'warn',
        '@stylistic/js/semi-spacing': 'warn',
        '@stylistic/js/no-floating-decimal': 'warn',
        '@stylistic/js/no-multi-spaces': ['warn', { ignoreEOLComments: true }],
        '@stylistic/js/no-multiple-empty-lines': ['warn', { max: 2, maxEOF: 0 }],
        '@stylistic/js/object-curly-spacing': ['warn', 'always'],
        '@stylistic/js/space-in-parens': 'warn',
        '@stylistic/js/key-spacing': 'warn',
        '@stylistic/js/object-property-newline': 'off',
        '@stylistic/js/spaced-comment': 'warn',
        '@stylistic/js/computed-property-spacing': 'warn',
        '@stylistic/js/object-curly-newline': ['warn', {
          ObjectExpression: { 'consistent': true },
          ObjectPattern: { 'consistent': true },
          ImportDeclaration: 'never',
          ExportDeclaration: 'never'
        }],
        '@stylistic/js/padded-blocks': ['warn', { blocks: 'never', classes: 'always', switches: 'never' }],
        '@stylistic/js/space-infix-ops': 'off',
        '@stylistic/js/space-before-function-paren': ['warn', 'never']
    }
  }
];