eslint.config.mjs

import { fixupConfigRules } from "@eslint/compat";
import globals from "globals";
import tsParser from "@typescript-eslint/parser";
import path from "node:path";
import { fileURLToPath } from "node:url";
import js from "@eslint/js";
import { FlatCompat } from "@eslint/eslintrc";

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
const compat = new FlatCompat({
    baseDirectory: __dirname,
    recommendedConfig: js.configs.recommended,
    allConfig: js.configs.all
});

export default [...fixupConfigRules(compat.extends(
    "eslint:recommended",
    "plugin:@typescript-eslint/recommended",
)), {
    languageOptions: {
        globals: {
            ...globals.browser,
            ...globals.mocha,
            ...globals.node,
        },

        parser: tsParser,
        ecmaVersion: 5,
        sourceType: "module",

        parserOptions: {
            project: ["client/tsconfig.json", "server/tsconfig.json"],
            tsconfigRootDir: __dirname,
        },
    },

    rules: {
        "space-infix-ops": "error",
        "space-in-parens": "error",
        "keyword-spacing": "error",
        "space-before-blocks": "error",
        "prefer-arrow-callback": "error",
        "arrow-spacing": "error",

        "object-curly-spacing": "error",
        "@typescript-eslint/explicit-function-return-type": "off",
        "@typescript-eslint/array-type": "error",
        "@typescript-eslint/no-unused-vars": "off",
        "no-useless-escape": "off",
        "no-undef": "off",
        "@typescript-eslint/ban-ts-ignore": "off",
        "no-control-regex": "off",
        "@typescript-eslint/camelcase": "off",
        "@typescript-eslint/explicit-module-boundary-types": "off",
        "@typescript-eslint/no-this-alias": "off",
        "@typescript-eslint/no-non-null-assertion": "off",
        "@typescript-eslint/explicit-member-accessibility": "error",
        "@typescript-eslint/consistent-type-assertions": "error",

        "indent": ["error", 2, {
            SwitchCase: 1,
            ignoreComments: true,

            CallExpression: {
                arguments: "first",
            },

            FunctionDeclaration: {
                parameters: "first",
            },

            FunctionExpression: {
                parameters: "first",
            },
        }],

        "@typescript-eslint/interface-name-prefix": "off",
        "@typescript-eslint/member-delimiter-style": "off",
        "@typescript-eslint/member-ordering": "off",
        "@typescript-eslint/no-empty-function": "error",
        "@typescript-eslint/no-empty-interface": "error",
        "@typescript-eslint/no-explicit-any": "off",
        "@typescript-eslint/no-inferrable-types": "off",
        "@typescript-eslint/no-require-imports": "error",
        "@typescript-eslint/no-use-before-define": "off",
        "@typescript-eslint/no-var-requires": "error",
        "@typescript-eslint/prefer-for-of": "error",
        "@typescript-eslint/prefer-namespace-keyword": "error",

        "quotes": ["error", "double", {
            avoidEscape: true,
            allowTemplateLiterals: true,
        }],

        "@typescript-eslint/restrict-plus-operands": "off",
        "semi": ["error", "always"],
        "@typescript-eslint/triple-slash-reference": "error",
        "@typescript-eslint/unified-signatures": "error",
        camelcase: "off",
        "capitalized-comments": ["off", "never"],
        "comma-spacing": ["error"],
        "comma-dangle": ["error", "always-multiline"],
        curly: "error",
        "default-case": "error",
        "dot-notation": "off",
        "eol-last": "off",
        eqeqeq: ["error", "smart"],
        "guard-for-in": "off",
        "id-blacklist": "off",
        "id-match": "error",

        "max-len": ["error", {
            ignoreRegExpLiterals: true,
            ignoreStrings: true,
            ignorePattern: "^\\s*\\*",
            code: 140,
        }],

        "new-parens": "error",
        "no-bitwise": "error",
        "no-caller": "error",
        "no-cond-assign": "error",
        "no-console": "off",
        "no-constant-condition": "off",
        "no-debugger": "error",
        "no-duplicate-case": "error",
        "no-empty": "error",
        "no-eval": "error",
        "no-fallthrough": "error",
        "no-invalid-this": "off",
        "no-irregular-whitespace": "error",
        "no-multiple-empty-lines": "off",
        "no-new-wrappers": "error",
        "no-redeclare": "error",
        "no-return-await": "error",
        "no-sequences": "error",

        "no-shadow": ["off", {
            hoist: "all",
        }],

        "no-sparse-arrays": "error",
        "no-trailing-spaces": "error",
        "no-underscore-dangle": "off",
        "no-unused-labels": "error",
        "no-var": "error",
        "no-void": "error",
        "one-var": ["error", "never"],
        "prefer-const": "error",
        "@typescript-eslint/prefer-readonly": "error",
        radix: "error",
        "spaced-comment": "off",
        "use-isnan": "error",
    },
}];