.eslintrc.json

{
    "env": {
        "node": true,
        "commonjs": true,
        "es2021": true
    },
    "extends": "eslint:recommended",
    "parserOptions": {
        "ecmaVersion": 12
    },
    "rules": {
        "no-console": "warn",
        //* Avoid Bugs
        "no-undef": "error",
        "semi": "error",
        "semi-spacing": "error",
        //* Best Practices
        "eqeqeq": "warn",
        "no-invalid-this": "error",
        "no-return-assign": "error",
        "no-unused-expressions": ["error", { "allowTernary": true }],
        "no-useless-concat": "error",
        "no-useless-return": "error",
        "no-constant-condition": "warn",
        "no-unused-vars": ["warn", { "argsIgnorePattern": "req|res|next|__" }],
        //* Enhance Readability
        "indent": ["error", 4, { "SwitchCase": 1 }],
        "no-mixed-spaces-and-tabs": "warn",
        "space-before-blocks": "error",
        "space-in-parens": "error",
        "space-infix-ops": "error",
        "space-unary-ops": "error",
        "quotes": ["warn", "single"],
        //
        "max-len": ["error", { "code": 200 }],
        "max-lines": ["error", { "max": 500 }],
        "keyword-spacing": "error",
        "multiline-ternary": ["error", "never"],
        "no-mixed-operators": "error",
        //
        "no-multiple-empty-lines": ["error", { "max": 2, "maxEOF": 1 }],
        "no-whitespace-before-property": "error",
        "nonblock-statement-body-position": "error",
        "object-property-newline": [
            "error",
            { "allowAllPropertiesOnSameLine": true }
        ],
        //* ES6
        "arrow-spacing": "error",
        "no-confusing-arrow": "error",
        "no-duplicate-imports": "error",
        "no-var": "error",
        "object-shorthand": "off",
        "prefer-const": "error",
        "prefer-template": "warn"
    }
}