.eslintrc

{
  "parserOptions": {
    "ecmaVersion": 2018,
    "sourceType": "module"
  },
  "env": {
    "node": true,
    "mocha": true,
    "es6": true
  },
  "plugins": [
    "no-null"
  ],
  "rules": {
    // # Possible errors
    //
    // disallow assignment in conditional expressions
    "no-cond-assign": 2,
    // disallow use of console.log()
    "no-console": 2,
    // disallow use of constant expressions in conditions
    "no-constant-condition": 2,
    // disallow control characters in regular expressions
    "no-control-regex": 2,
    // disallow use of debugger
    "no-debugger": 2,
    // disallow duplicate arguments in functions
    "no-dupe-args": 2,
    // disallow duplicate keys when creating object literals
    "no-dupe-keys": 2,
    // disallow a duplicate switch case label
    "no-duplicate-case": 2,
    // disallow empty block statements
    "no-empty": 2,
    // disallow the use of empty character classes in regular expressions
    "no-empty-character-class": 2,
    // disallow assigning to the exception in a catch block
    "no-ex-assign": 2,
    // disallow double-negation boolean casts in a boolean context
    "no-extra-boolean-cast": 2,
    // disallow unnecessary semicolons
    "no-extra-semi": 2,
    // disallow overwriting functions written as function declarations
    "no-func-assign": 2,
    // disallow function or variable declarations in nested blocks
    "no-inner-declarations": 2,
    // disallow invalid regular expression strings in the RegExp constructor
    "no-invalid-regexp": 2,
    // disallow irregular whitespace outside of strings and comments
    "no-irregular-whitespace": 2,
    // disallow negation of the left operand of an in expression
    "no-negated-in-lhs": 2,
    // disallow the use of object properties of the global object (Math and JSON) as functions
    "no-obj-calls": 2,
    // disallow multiple spaces in a regular expression literal
    "no-regex-spaces": 2,
    // disallow sparse arrays
    "no-sparse-arrays": 2,
    // Avoid code that looks like two expressions but is actually one
    "no-unexpected-multiline": 2,
    // disallow unreachable statements after a return, throw, continue, or break statement
    "no-unreachable": 2,
    // disallow comparisons with the value NaN
    "use-isnan": 2,
    // ensure that the results of typeof are compared against a valid string
    "valid-typeof": 2,
    // enforces that a for loop update clause moves the counter in the right direction.
    "for-direction": 2,
    // enforces that a return statement is present in property getters.
    "getter-return": 2,
    // disallow assignments that can lead to race conditions due to usage of await or yield
    "require-atomic-updates": 2,

    // # Best practices
    //
    // enforces return statements in callbacks of array’s methods
    "array-callback-return": 2,
    // require curly braces for all control statements
    "curly": 2,
    // require default case in switch statements
    "default-case": 2,
    // enforces consistent newlines before or after dots
    "dot-location": [2, "property"],
    // require foo.bar instead of foo['bar']
    "dot-notation": 2,
    // require the use of === and !==
    "eqeqeq": 2,
    // make sure for-in loops have an if statement
    "guard-for-in": 2,
    // disallow the use of alert, confirm, and prompt
    "no-alert": 2,
    // disallow use of arguments.caller or arguments.callee
    "no-caller": 2,
    // disallow lexical declarations in case clauses
    "no-case-declarations": 2,
    // disallow use of empty functions
    "no-empty-function": 2,
    // disallow use of empty destructuring patterns
    "no-empty-pattern": 2,
    // disallow use of eval()
    "no-eval": 2,
    // disallow unnecessary function binding
    "no-extra-bind": 2,
    // disallow fallthrough of case statements
    "no-fallthrough": 2,
    // disallow the use of leading or trailing decimal points in numeric literals
    "no-floating-decimal": 2,
    // disallow var and named functions in global scope
    "no-implicit-globals": 2,
    // disallow use of eval()-like methods
    "no-implied-eval": 2,
    // disallow this keywords outside of classes or class-like objects
    "no-invalid-this": 2,
    // disallow usage of __iterator__ property
    "no-iterator": 2,
    // disallow use of labeled statements
    "no-labels": 2,
    // disallow unnecessary nested blocks
    "no-lone-blocks": 2,
    // disallow creation of functions within loops
    "no-loop-func": 2,
    // disallow the use of magic numbers
    "no-magic-numbers": [2, {"ignore": [-1, 0, 1, 2]}],
    // disallow use of multiple spaces
    "no-multi-spaces": 2,
    // disallow use of multiline strings
    "no-multi-str": 2,
    // disallow use of the new operator when not part of an assignment or comparison
    "no-new": 2,
    // disallow use of new operator for Function object
    "no-new-func": 2,
    // disallows creating new instances of String,Number, and Boolean
    "no-new-wrappers": 2,
    // disallow use of octal literals
    "no-octal": 2,
    // disallow use of octal escape sequences in string literals, such as var foo = "Copyright \251";
    "no-octal-escape": 2,
    // disallow usage of __proto__ property
    "no-proto": 2,
    // disallow declaring the same variable more than once
    "no-redeclare": 2,
    // disallow use of assignment in return statement
    "no-return-assign": 2,
    // disallow use of javascript: urls
    "no-script-url": 2,
    // disallow assignments where both sides are exactly the same
    "no-self-assign": 2,
    // disallow comparisons where both sides are exactly the same
    "no-self-compare": 2,
    // disallow use of the comma operator
    "no-sequences": 2,
    // disallow unmodified conditions of loops
    "no-unmodified-loop-condition": 2,
    // disallow usage of expressions in statement position
    "no-unused-expressions": 2,
    // disallow unnecessary .call() and .apply()
    "no-useless-call": 2,
    // disallow unnecessary concatenation of literals or template literals
    "no-useless-concat": 2,
    // disallow use of the void operator
    "no-void": 2,
    // disallow use of the with statement
    "no-with": 2,
    // require use of the second argument for parseInt()
    "radix": 2,
    // require immediate function invocation to be wrapped in parentheses
    "wrap-iife": 2,

    // # Variables
    //
    // disallow the catch clause parameter name being the same as a variable in the outer scope
    "no-catch-shadow": 2,
    // disallow deletion of variables
    "no-delete-var": 2,
    // disallow declaration of variables already declared in the outer scope
    "no-shadow": 2,
    // disallow shadowing of names such as arguments
    "no-shadow-restricted-names": 2,
    // disallow use of undeclared variables
    "no-undef": 2,
    // disallow use of undefined when initializing variables
    "no-undef-init": 2,
    // disallow declaration of variables that are not used in the code
    "no-unused-vars": 2,

    // # Stylistic issues
    //
    // enforce no spacing inside array brackets
    "array-bracket-spacing": 2,
    // enforce spaces inside of single line blocks
    "block-spacing": 2,
    // Enforce one true brace style
    "brace-style": [2, "stroustrup"],
    // require camel case names
    "camelcase": 2,
    // require space after comma, no space before
    "comma-spacing": 2,
    // require commas at end of line (no comma-first style)
    "comma-style": 2,
    // disallow spaces inside computed properties
    "computed-property-spacing": 2,
    // require file to end with a newline
    "eol-last": 2,
    // require indentation of 2 spaces
    "indent": [2, 2],
    // require space after colon: no space before
    "key-spacing": 2,
    // enforce space before and after keywords
    "keyword-spacing": 2,
    // require LF line breaks
    "linebreak-style": [2, "unix"],
    // require a capital letter for constructors
    "new-cap": 2,
    // disallow the omission of parentheses when invoking a constructor with no arguments
    "new-parens": 2,
    // disallow use of the Array constructor
    "no-array-constructor": 2,
    // disallow use of bitwise operators
    "no-bitwise": 2,
    // disallow use of the continue statement
    "no-continue": 2,
    // disallow if as the only statement in an else block
    "no-lonely-if": 2,
    // disallow negated if-else conditions
    "no-negated-condition": 2,
    // disallow nested ternary expressions
    "no-nested-ternary": 2,
    // disallow the use of the Object constructor
    "no-new-object": 2,
    // disallow space between function identifier and application
    "no-spaced-func": 2,
    // disallow trailing whitespace at the end of lines
    "no-trailing-spaces": 2,
    // disallow _dangling_ underscores in identifiers
    "no-underscore-dangle": 2,
    // disallow the use of ternary operators when a simpler alternative exists
    "no-unneeded-ternary": [2, {"defaultAssignment": true}],
    // disallow whitespace before properties
    "no-whitespace-before-property": 2,
    // require or disallow padding inside curly braces
    "object-curly-spacing": 2,
    // disallow one declaration declaring multiple variables
    "one-var": [2, "never"],
    // require assignment operator shorthand where possible
    "operator-assignment": 2,
    // enforce operators to be placed before line breaks
    "operator-linebreak": 2,
    // disallow empty lines at the beginning and end of blocks
    "padded-blocks": [2, "never"],
    // require use of 'single-quotes'
    "quotes": [2, "single"],
    // require semicolons
    "semi": 2,
    // enforce no space before; and space after semicolons
    "semi-spacing": 2,
    // require a space before blocks
    "space-before-blocks": 2,
    // disallow a space before function opening parenthesis
    "space-before-function-paren": [2, "never"],
    // disallow spaces inside parentheses
    "space-in-parens": 2,
    // require spaces around operators
    "space-infix-ops": 2,
    // spaces before/after unary operators (required for words, disallowed for nonwords)
    "space-unary-ops": 2,
    // require a space immediately following the // or /* in a comment
    "spaced-comment": 2,
    // prefer the use of object spread over Object.assign
    "prefer-object-spread": 2,
    // require an empty line between class members
    "lines-between-class-members": 2,

    // # ECMAScript 6
    //
    // require space before/after arrow function's arrow
    "arrow-spacing": 2,
    // verify calls of super() in constructors
    "constructor-super": 2,
    // disallow modifying variables of class declarations
    "no-class-assign": 2,
    // disallow modifying variables that are declared using const
    "no-const-assign": 2,
    // disallow duplicate name in class members
    "no-dupe-class-members": 2,
    // disallow use of the new operator with the Symbol object
    "no-new-symbol": 2,
    // disallow use of this/super before calling super() in constructors
    "no-this-before-super": 2,
    // disallow unnecessary constructor
    "no-useless-constructor": 2,
    // Only allow let/const
    "no-var": 2,
    // require method shorthand syntax for object literals
    "object-shorthand": [2, "methods"],
    // suggest using arrow functions as callbacks
    "prefer-arrow-callback": 2,
    // suggest using const declaration for variables that are never reassigned after declared
    "prefer-const": 2,
    // suggest using the rest parameters instead of arguments
    "prefer-rest-params": 2,
    // suggest using the spread operator instead of .apply()
    "prefer-spread": 2,
    // suggest using template literals instead of strings concatenation
    "prefer-template": 2,
    // disallow generator functions that do not have yield
    "require-yield": 2,
    // disallow spaces inside template ${curly block}
    "template-curly-spacing": 2,

    // Prefer undefined to null
    "no-null/no-null": 2,
  }
}