.eslintrc.json

{
    "extends": [
        "airbnb-base",
        "plugin:mocha/recommended",
        "prettier"
    ],
    "plugins": [
        "@typescript-eslint",
        "chai-friendly",
        "mocha",
        "prettier"
    ],
    "parser": "@typescript-eslint/parser",
    "settings": {
        // https://github.com/benmosher/eslint-plugin-import/issues/1615
        "import/resolver": {
            "node": {
                "extensions": [".js", ".ts", ".json"]
            }
        }
    },
    "rules": {
        // airbnb-base enables func-names, but conflicts with Mocha conventions
        // https://mochajs.org/#arrow-functions
        // https://github.com/airbnb/javascript/issues/433
        "func-names": 0,
        // airbnb-base enables no-unused-expressions, but conflicts with chai assertion expressions
        "no-unused-expressions": 0,
        "chai-friendly/no-unused-expressions": 2,

        "prettier/prettier": "error",
        "import/no-extraneous-dependencies": [
            "error",
            {
                "devDependencies": true
            }
        ],
        "import/prefer-default-export": "off",
        "no-unused-vars": "off",
        "@typescript-eslint/no-unused-vars": [
            "error", {
                "argsIgnorePattern": "^_"
            }
        ],
        // https://github.com/benmosher/eslint-plugin-import/issues/1615
        "import/extensions": [
            "error",
            "ignorePackages",
            {
                "js": "never",
                "mjs": "never",
                "ts": "never"
            }
        ],
        // no-use-before-define conflicts with clean code top-to-bottom rules
        // https://github.com/eslint/eslint/issues/10589
        // https://github.com/typescript-eslint/typescript-eslint/blob/v4.2.0/packages/eslint-plugin/docs/rules/no-use-before-define.md
        "no-use-before-define": "off",
        "@typescript-eslint/no-use-before-define": [
            "error", { 
                "functions": false, 
                "classes": false, 
                "variables": false,
                "typedefs": false,
                "enums": false
            }
        ],
        "mocha/no-setup-in-describe": "off",
        // https://github.com/typescript-eslint/typescript-eslint/blob/v4.0.0/packages/eslint-plugin/docs/rules/no-shadow.md
        "no-shadow": "off",
        "@typescript-eslint/no-shadow": ["error"],
        // https://github.com/typescript-eslint/typescript-eslint/blob/v4.0.0/packages/eslint-plugin/docs/rules/no-redeclare.md
        "no-redeclare": "off",
        "@typescript-eslint/no-redeclare": ["error"]
    },
    "env": {
        "mocha": true
    }
}