.eslintrc

{
  "rules": {
    // common
    "indent": ["warn", 2, {"SwitchCase": 1}], // specify tab or space width for your code
    "quotes": ["error", "single", { "allowTemplateLiterals": true }], // specify whether backticks, double or single quotes should be used
    "linebreak-style": ["error", "unix"], // disallow mixed 'LF' and 'CRLF' as linebreaks
    "semi": ["error", "always"], // require or disallow use of semicolons instead of ASI
    // errors
    "no-extra-parens": ["error", "functions"], // disallow unnecessary parentheses
    "no-unexpected-multiline": ["error"], // Avoid code that looks like two expressions but is actually one
    "valid-jsdoc": ["warn"], // Ensure JSDoc comments are valid
    // best practices
    "block-scoped-var": ["error"], // treat var statements as if they were block scoped
    "curly": ["error", "all"], // specify curly brace conventions for all control statements
    "default-case": ["error"], // require default case in switch statements
    "dot-notation": ["error"], // encourages use of dot notation whenever possible
    "dot-location": ["error", "property"], // enforces consistent newlines before or after dots
    "eqeqeq": ["error", "smart"], // require the use of === and !==
    "guard-for-in": ["error"], // make sure for-in loops have an if statement
    "no-alert": ["error"], // disallow the use of alert, confirm, and prompt
    "no-caller": ["error"], // disallow use of arguments.caller or arguments.callee
    "no-eq-null": ["error"], // disallow comparisons to null without a type-checking operator
    "no-eval": ["error"], // disallow use of eval()
    "no-extend-native": ["error"], // disallow adding to native types
    "no-extra-bind": ["error"], // disallow unnecessary function binding
    "no-fallthrough": ["error"], // disallow fallthrough of case statements (recommended)
    "no-floating-decimal": ["error"], // disallow the use of leading or trailing decimal points in numeric literals
    "no-implied-eval": ["error"], // disallow use of eval()-like methods
    "no-iterator": ["error"], // disallow usage of __iterator__ property
    "no-labels": ["error"], // disallow use of labeled statements
    "no-lone-blocks": ["error"], // disallow unnecessary nested blocks
    "no-loop-func": ["error"], // disallow creation of functions within loops
    "no-multi-spaces": ["error"], // disallow use of multiple spaces
    "no-multi-str": ["error"], // disallow use of multiline strings
    "no-native-reassign": ["error"], // disallow reassignments of native objects
    "no-new-func": ["error"], // disallow use of new operator for Function object
    "no-new-wrappers": ["error"], // disallows creating new instances of String,Number, and Boolean
    "no-new": ["error"], // disallow use of the new operator when not part of an assignment or comparison
    "no-octal-escape": ["error"], // disallow use of octal escape sequences in string literals, such as var foo = "Copyright \"error"51";
    "no-octal": ["error"], // disallow use of octal literals (recommended)
    "no-param-reassign": ["warn", {"props": false}], // disallow reassignment of function parameters
    "no-proto": ["error"], // disallow usage of __proto__ property
    "no-redeclare": ["error", {"builtinGlobals": true}], // disallow declaring the same variable more than once (recommended)
    "no-return-assign": ["error"], // disallow use of assignment in return statement
    "no-script-url": ["error"], // disallow use of javascript: urls.
    "no-self-compare": ["error"], // disallow comparisons where both sides are exactly the same
    "no-sequences": ["error"], // disallow use of the comma operator
    "no-throw-literal": ["error"], // restrict what can be thrown as an exception
    "no-unused-expressions": ["error"], // disallow usage of expressions in statement position
    "no-useless-call": ["error"], // disallow unnecessary .call() and .apply()
    "no-useless-concat": ["error"], // disallow unnecessary concatenation of literals or template literals
    "no-void": ["error"], // disallow use of the void operator
    "no-with": ["error"], // disallow use of the with statement
    "radix": ["error"], // require use of the second argument for parseInt()
    "wrap-iife": ["error"], // require immediate function invocation to be wrapped in parentheses
    // Variables
    "no-delete-var": ["error"], // disallow deletion of variables (recommended)
    "no-label-var": ["error"], // disallow labels that share a name with a variable
    "no-shadow-restricted-names": ["error"], // disallow shadowing of names such as arguments
    "no-undef-init": ["error"], // disallow use of undefined when initializing variables
    "no-undef": ["error"], // disallow use of undeclared variables unless mentioned in a /*global */ block (recommended)
    "no-unused-vars": ["error"], // disallow declaration of variables that are not used in the code (recommended)
    // nodejs
    "callback-return": ["error", ["callback", "cb", "next"]], // enforce return after a callback
    "handle-callback-err": ["error", "^(err\\d?|error\\d?|^.+Err$|^.+Error$)$"], // enforce error handling in callbacks
    "no-mixed-requires": ["error", false], // disallow mixing regular variable and require declarations
    "no-new-require": ["error"], // disallow use of new operator with the require function
    "no-path-concat": ["error"], // disallow string concatenation with __dirname and __filename
    "no-sync": ["error"], // disallow use of synchronous methods
    // Stylistic
    "array-bracket-spacing": ["warn", "never"], // enforce spacing inside array brackets
    "block-spacing": ["warn", "never"], // disallow or enforce spaces inside of single line blocks
    "brace-style": ["warn", "1tbs", { "allowSingleLine": false }], // enforce one true brace style
    "camelcase": ["warn", {"properties": "always"}], // require camel case names
    "comma-spacing": ["warn", {"before": false, "after": true}], // enforce spacing before and after comma
    "comma-style": ["warn", "last"], // enforce one true comma style
    "computed-property-spacing": ["warn", "never"], // require or disallow padding inside computed properties
    "consistent-this": ["warn", "self"], // enforce consistent naming when capturing the current execution context
    "eol-last": ["off"], // enforce newline at the end of file, with no multiple empty lines
    "key-spacing": ["warn", {"beforeColon": false, "afterColon": true}], // enforce spacing between keys and values in object literal properties
    "max-nested-callbacks": ["warn", 6], // specify the maximum depth callbacks can be nested
    "new-cap": ["warn", {"capIsNewExceptions": ["Router"]}], // require a capital letter for constructors
    "new-parens": ["warn"], // disallow the omission of parentheses when invoking a constructor with no arguments
    "newline-after-var": ["off", "always"], // require or disallow an empty newline after variable declarations
    "no-array-constructor": ["warn"], // disallow use of the Array constructor
    "no-lonely-if": ["warn"], // disallow if as the only statement in an else block
    "no-mixed-spaces-and-tabs": ["error"], // disallow mixed spaces and tabs for indentation (recommended)
    "no-multiple-empty-lines": ["warn", {"max": 1}], // disallow multiple empty lines
    "no-nested-ternary": ["warn"], // disallow nested ternary expressions
    "no-new-object": ["warn"], // disallow the use of the Object constructor
    "no-spaced-func": ["warn"], // disallow space between function identifier and application
    "no-trailing-spaces": ["warn", { "skipBlankLines": false }], // disallow trailing whitespace at the end of lines
    "no-unneeded-ternary": ["error"], // disallow the use of Boolean literals in conditional expressions
    "operator-linebreak": ["warn", "after"], // enforce operators to be placed before or after line breaks
    "quote-props": ["error", "as-needed"], // require quotes around object literal property names
    "semi-spacing": ["warn", {"before": false, "after": true}], // enforce spacing before and after semicolons
    "space-in-parens": ["warn", "never"], // require or disallow spaces inside parentheses
    "space-unary-ops": ["warn", {"words": true, "nonwords": false}], // require or disallow spaces before/after unary operators
    "spaced-comment": ["warn", "always"], // require or disallow a space immediately following the // or /* in a comment
    "wrap-regex": ["warn"], // require regex literals to be wrapped in parentheses
    "no-console": ["off"]
  },
  "parserOptions": {
    "ecmaVersion": 2018,
    "sourceType": "module"
  },
  "env": {
    "node": true,
    "es6": true,
    "mocha": true
  },
  "extends": "eslint:recommended",
  "globals": {
    "should": true
  }
}