.eslintrc.json

{
    "env": {
        "browser": true,
        "node": true,
        "es6": true
    },
    "extends": "eslint:recommended",
    "globals": {
        "module": "readonly",
        "require": "readonly"
    },
    "parser": "@babel/eslint-parser",
    "parserOptions": {
        "ecmaVersion": 2018,
        "requireConfigFile": false,
        "sourceType": "module"
    },
    "rules": {
        "indent": [
            "error",
            4
        ],
        "linebreak-style": [
            "error",
            "unix"
        ],
        "quotes": [
            "error",
            "single"
        ],
        "semi": [
            "error",
            "always"
        ],
        "brace-style": [
            "error",
            "1tbs",
            { "allowSingleLine": false }
        ],
        "curly": "error",
        "no-trailing-spaces": "error",
        "no-multi-spaces": "error",
        "keyword-spacing": [
            "error",
            { "before": true, "after": true }
        ],
        "comma-spacing": [
            "error",
            { "before": false, "after": true }
        ],
        "arrow-spacing": [
            "error",
            { "before": true, "after": true }
        ],
        "key-spacing": [
            "error",
            { "beforeColon": false, "afterColon": true, "mode": "strict" }
        ],
        "func-call-spacing": ["error", "never"],
        "space-infix-ops": "error",
        "space-before-function-paren": ["error", "never"],
        "space-before-blocks": "error",
        "no-console": [
            "error",
            { "allow": ["warn", "error"] }
        ],
        "comma-dangle": ["error", "always-multiline"],
        "comma-style": ["error", "last"],
        "max-len": ["error", { "code": 100, "tabWidth": 2 }],
        "eol-last": ["error", "always"],
        "no-extra-parens": "error",
        "arrow-parens": ["error", "as-needed"],
        "no-unused-vars": [
            "error",
            {
                "argsIgnorePattern": "^_",
                "varsIgnorePattern": "^_"
            }
        ],
        "prefer-const": ["error"],
        "no-var": "error",
        "eqeqeq": "error"
    },
    "overrides": [
        {
            "files": [
                "tests/**/*.js"
            ],
            "env": {
                "jest": true,
                "node": true
            }
        }
    ]
}