.eslintrc.js

module.exports = {
    "env": {
        "browser": true,
        "es6": true,
        "node": true,
        "mocha": true
    },
    "extends": "eslint:recommended",
    "parserOptions": {
        "ecmaVersion": 2018,
        "sourceType": "module"
    },
    "rules": {
        // References

        "prefer-const": [
            "error", 
            {
                "destructuring": "any",
                "ignoreReadBeforeAssign": false
            }
        ],

        // Objects

        "no-new-object": [
            "error"
        ],
        /* expects that the shorthand will be used whenever possible */
        "object-shorthand": [
            "off"
        ],
        /* disallows quotes around object literal property names that are not strictly required */
        "quote-props": [
            "error", 
            "as-needed" 
        ],
        /* disallow use of Object.prototypes builtins directly */
        "no-prototype-builtins": [
            "error"
        ],
 
        // Arrays

        "no-array-constructor": [
            "error"
        ],

        // String
        "quotes": [
            "error",
            "single"
        ],
        /* suggest using template literals instead of string concatenation */
        "prefer-template": [
            "error"
        ],

        // Functions

        "prefer-rest-params": [
            "error"
        ],
        "prefer-spread": [
            "error"
        ],
        "no-new-func": [
            "error"
         ],
         /* require or disallow named function expressions */
         "func-names": [
            "error",
            "always"
         ],
         /* require a space before function parenthesis */
        "space-before-function-paren": [
           　"error", 
             {
                "anonymous": "always",
                "named": "always",
                "asyncArrow": "always"
   　　　　　  }
　　　　　],
        /* require Space Before Blocks */
        "space-before-blocks": [
            "error",
            "always"
        ],
        /* disallow Reassignment of Function Parameters */
        "no-param-reassign": [
            "error"
        ],

        // Arrow Functions
    
        "prefer-arrow-callback": [
            "error"
        ],
        /* require space before/after arrow function’s arrow */
        "arrow-spacing": [
            "error",
             { "before": true, "after": true }
        ],
        "arrow-parens": [
            "error",
            "always"
        ],
        "arrow-body-style": [
            "error",
            "as-needed"
        ],

        // Modules

        "no-duplicate-imports": [
            "error",
            { "includeExports": true }
        ],

        // Iterators and Generators

        "generator-star-spacing": [
            "error",
            {"before": false, "after": true}
        ],

        // Variables

        "no-multi-assign": [
            "off",
        ],
        "no-plusplus": [
            "error",
            { "allowForLoopAfterthoughts": true }
        ],
        /* require Variable Declarations to be at the top of their scope */
        "vars-on-top": [
            "error"
        ],
        /* require initialization in variable declarations */
        "init-declarations": [
            "error",
            "always" 
        ],

        // Comparison Operators & Equality

        /* use shortcuts for booleans, but explicit comparisons for strings and numbers */
        "eqeqeq": [
            "error",
            "always"
        ],
        "no-nested-ternary": [
            "error"
        ],
        "no-unneeded-ternary": [
            "error"
        ],
        /* enclosing complex expressions by parentheses clarifies the developer’s intention, which makes the code more readable */
        "no-mixed-operators": [
            "error",
            {
                "groups": [
                    ["+", "-", "*", "/", "%", "**"],
                    ["&", "|", "^", "~", "<<", ">>", ">>>"],
                    ["==", "!=", "===", "!==", ">", ">=", "<", "<="],
                    ["&&", "||"],
                    ["in", "instanceof"]
                ],
                "allowSamePrecedence": true
            }
        ],

        // Blocks

        "brace-style": [
            "error",
            "1tbs", 
            { "allowSingleLine": true }
        ],
        "no-else-return": [
            "error", 
            { allowElseIf: false }
        ],

        // Control Statements

        /* require Default Case in Switch Statements */
        "default-case": [
            "error", 
        ],

        // Comments

        /* enforce capitalization of the first letter of a comment */
        "capitalized-comments": [
            "error",
            "always",
            {
                "ignorePattern": "pragma|ignored",
                "ignoreInlineComments": true
            }
        ],
        /* requires a whitespace (space or tab) beginning a comment */
        "spaced-comment": [
            "error",
            "always"
        ],
        /* enforce position of line comments */
        "line-comment-position": [
            "error",
            { "position": "above" }
        ],
        /* enforce position of line comments */
        "multiline-comment-style": [
            "error",
            "starred-block"
        ],
        /* disallow inline comments after code */
        "no-inline-comments": [
            "error"
        ],

        // Whitespace

        "indent": [
            "error", 
            3
        ],
        "space-before-blocks": [
            "error",
            "always"
        ],
        /* enforce consistent spacing before and after keywords */
        "keyword-spacing": [
            "error"
        ],
        "space-infix-ops": [
            "error", 
            { "int32Hint": true }
        ],
        "eol-last": [
            "error"
        ],
        "newline-per-chained-call": [
            "error",
            { "ignoreChainWithDepth": 2 }
        ],
        /* disallow whitespace before properties */
        "no-whitespace-before-property": [
            "error"
        ],
        "space-in-parens": [
            "error",
            "never"
        ],
        "array-bracket-spacing": [
            "error",
            "never"
        ],
        "object-curly-spacing": [
            "error",
            "always"
        ],
        /* enforce a maximum line length */
        "max-len": [
            "error",
            { 
                "code": 100, 
                "comments": 120,
                "ignoreTrailingComments": false,
                "ignoreUrls": true,
                "ignoreStrings": true,
                "ignoreTemplateLiterals": true,
                "ignoreRegExpLiterals": true
           }
        ],
        /* disallow spaces inside of blocks after opening block and before closing block */
        "block-spacing": [
            "error",
            "never"
        ],
        /* enforces spacing around commas */
        "comma-spacing": [
            "error",
            { "before": false, "after": true }
        ],
        "computed-property-spacing": [
            "error",
            "never"
        ],
        "func-call-spacing": [
            "error",
            "never"
        ],
        "key-spacing": [
            "error",
            { "beforeColon": false }
        ],
        "no-trailing-spaces": [
            "error"
        ],
        "no-multiple-empty-lines": [
            "error",
            { "max": 2 }
        ],
        "rest-spread-spacing": [
            "error",
            "never"
        ],
        
        // Commas
        
        "comma-style": [
            "error", 
            "last"
        ],
         /* disallows trailing commas */
        "comma-dangle": [
            "error", 
            "never"
        ],

        // Semi

        "semi": [
            "error",
            "always"
        ],

        // Naming Conventions

        "camelcase": [
            "error"
        ],
        /* require constructor names to begin with a capital letter */
        "new-cap": [
            "error"
        ],

        "no-console": [
            "off"
        ]
    }
};