.eslintrc.js

module.exports = {
    "env": {
        "node": true,
        "commonjs": true,
        "es6": true,
        "mocha": true
    },
    "extends": [
        "eslint:recommended"
    ],
    "parserOptions": {
        "ecmaVersion": 2018
    },
    "rules": {
        // Bad Practices
        "curly": "error",
        "no-await-in-loop": "error",
        "no-eval": "error",
        "no-implicit-globals": "error",
        "no-lone-blocks": "error",
        "no-return-await": "error",
        "no-self-compare": "error",
        "no-sequences": "error",
        "no-throw-literal": "error",
        "no-with": "error",
        "prefer-arrow-callback": [ "error", { "allowNamedFunctions": true } ],
        "prefer-promise-reject-errors": "error",
        "prefer-rest-params": "warn",
        "no-label-var": "error",
        "no-undefined": "off",
        "no-use-before-define": "error",
        "no-array-constructor": "error",
        "no-new-object": "error",
        "no-continue": "error",
        "no-unneeded-ternary": "error",

        // Common Mistakes
        "no-extra-bind": "warn",
        "no-floating-decimal": "warn",
        "no-multi-spaces": "warn",
        "no-useless-call": "warn",
        "no-useless-return": "warn",
        "require-await": "off",
        "no-mixed-operators": "warn",

        // Style
        "array-bracket-newline": [ "warn", "consistent" ],
        "array-bracket-spacing": [ "warn", "always" ],
        "array-element-newline": [ "warn", "consistent" ],
        "arrow-parens": [ "warn", "always" ],
        "arrow-spacing": "warn",
        "block-spacing": "warn",
        "brace-style": [ "warn", "allman", { "allowSingleLine": true } ],
        "camelcase": "warn",
        "comma-dangle": [ "warn", "never" ],
        "comma-spacing": [ "warn", { "before": false, "after": true } ],
        "comma-style": [ "warn", "last" ],
        "computed-property-spacing": [ "warn", "never" ],
        "consistent-this": [ "warn", "self" ],
        "eol-last": [ "warn", "always" ],
        "func-call-spacing": ["warn", "never"],
        "func-style": [ "warn", "declaration", { "allowArrowFunctions": true } ],
        "function-paren-newline": [ "warn", "multiline" ],
        "generator-star-spacing": [ "warn", { "before": true, "after": false } ],
        "id-length": [ "warn", { "min": 2, "exceptions": [ "_", "a", "b", "i", "x", "y", "z" ] } ],
        "indent": [
            "warn",
            4,
            {
                "SwitchCase": 1,
                "VariableDeclarator": 1,
                "outerIIFEBody": 1,
                "MemberExpression": 1,
                "FunctionDeclaration": {
                    "parameters": 1,
                    "body": 1
                },
                "FunctionExpression": {
                    "parameters": 1,
                    "body": 1
                },
                "CallExpression": {
                    "arguments": 1
                },
                "ArrayExpression": 1,
                "ObjectExpression": 1,
                "ImportDeclaration": 1,
                "flatTernaryExpressions": false
            }
        ],
        "key-spacing": [ "warn", { "beforeColon": false, "afterColon": true } ],
        "keyword-spacing": [
            "warn",
            {
                "overrides": {
                    "if": { "after": false },
                    "for": { "after": false },
                    "while": { "after": false }
                }
            }
        ],
        "lines-between-class-members": [ "warn", "always", { exceptAfterSingleLine: true } ],
        "new-parens": "warn",
        "newline-per-chained-call": [ "warn", { "ignoreChainWithDepth": 2 } ],
        "no-confusing-arrow": [ "warn", { "allowParens": false } ],
        "no-duplicate-imports": "warn",
        "no-lonely-if": "warn",
        "no-multi-assign": "warn",
        "no-multiple-empty-lines": [ "warn", { "max": 1, "maxBOF": 0, "maxEOF": 1 } ],
        "no-useless-computed-key": "warn",
        "no-useless-rename": [
            "error",
            {
                "ignoreDestructuring": false,
                "ignoreImport": false,
                "ignoreExport": false
            }
        ],
        "no-var": "warn",
        "no-whitespace-before-property": "warn",
        "object-curly-spacing": [ "warn", "always" ],
        "object-property-newline": [ "warn", { "allowAllPropertiesOnSameLine": true } ],
        "object-shorthand": [ "warn", "always" ],
        "one-var": [ "warn", "never" ],
        "operator-linebreak": [ "warn", "before" ],
        "padded-blocks": [ "warn", "never" ],
        "prefer-const": "warn",
        "prefer-object-spread": "warn",
        "prefer-template": "warn",
        "quote-props": [ "warn", "consistent-as-needed" ],
        "quotes": [ "warn", "single", { "avoidEscape": true, "allowTemplateLiterals": true } ],
        "semi": [ "error", "always" ],
        "semi-spacing": [ "warn", { "before": false, "after": true }  ],
        "space-before-blocks": "warn",
        "space-before-function-paren": [ "warn", "never" ],
        "space-in-parens": [ "warn", "never" ],
        "space-infix-ops": "warn",
        "space-unary-ops": "warn",
        "spaced-comment": [
            "warn",
            "always", {
                "line": {
                    "markers": [ "/" ],
                    "exceptions": [ "-", "+" ]
                },
                "block": {
                    "markers": ["!"],
                    "exceptions": ["*"],
                    "balanced": true
                }
            }
        ],
        "switch-colon-spacing": "warn",
        "template-curly-spacing": [ "warn", "always" ],
        "template-tag-spacing": "warn",
        "valid-jsdoc": [
            "warn",
            {
                "prefer": {
                    "arg": "param",
                    "argument": "param",
                    "class": "class",
                    "return": "returns",
                    "virtual": "abstract"
                },
                "preferType": {
                    "Boolean": "boolean",
                    "Number": "number",
                    "Object": "object",
                    "String": "string"
                },
                "requireReturn": true,
                "requireParamDescription": true,
                "requireParamType": true
            }
        ],
        "yield-star-spacing": [ "warn", "before" ],
        "yoda": [ "warn", "never", { "exceptRange": true } ]
    }
};