JSCS config file

.jscsrc

{
  "disallowImplicitTypeConversion": ["numeric", "boolean", "binary", "string"],
  "disallowKeywordsOnNewLine": ["else"],
  "disallowMixedSpacesAndTabs": true,
  "disallowTrailingWhitespace": true,
  "disallowTrailingComma": true,
  "disallowYodaConditions": true,
  "disallowKeywords": [ "with" ],
  "disallowMultipleLineBreaks": true,
  "disallowMultipleVarDecl": "strict",
  "disallowMultipleSpaces": true,
  "validateIndentation": 2,
  "disallowNewlineBeforeBlockStatements": true,
  "disallowQuotedKeysInObjects": true,
  "disallowSemicolons": true,
  "disallowSpaceAfterPrefixUnaryOperators": ["++", "--", "+", "-", "~", "!"],
  "disallowSpaceAfterObjectKeys": true,
  "disallowSpacesInCallExpression": true,
  "disallowSpacesInsideArrayBrackets": "all",
  "disallowSpacesInsideBrackets": true,
  "disallowSpacesInsideParentheses": true,
  "requireBlocksOnNewline": 1,
  "requireCamelCaseOrUpperCaseIdentifiers": true,
  "requireCapitalizedConstructors": true,
  "requireCommaBeforeLineBreak": true,
  "requireDotNotation": true,
  "requireLineBreakAfterVariableAssignment": true,
  "requireLineFeedAtFileEnd": true,
  "requireOperatorBeforeLineBreak": [
    "?",
    "=",
    "+",
    "-",
    "/",
    "*",
    "==",
    "===",
    "!=",
    "!==",
    ">",
    ">=",
    "<",
    "<="
  ],
  "requireParenthesesAroundIIFE": true,
  "requireSpaceAfterBinaryOperators": [
    "=",
    ",",
    "+",
    "-",
    "/",
    "*",
    "==",
    "===",
    "!=",
    "!==",
    "<",
    ">"
  ],
  "requireSpaceAfterKeywords": [
    "do",
    "for",
    "if",
    "else",
    "switch",
    "case",
    "try",
    "catch",
    "void",
    "while",
    "with",
    "return",
    "typeof"
  ],
  "requireSpaceBeforeBinaryOperators": [
    "=",
    "+",
    "-",
    "/",
    "*",
    "==",
    "===",
    "!=",
    "!==",
    "<",
    ">"
  ],
  "requireSpaceBeforeKeywords": [
    "else",
    "while",
    "catch"
  ],
  "requireSpacesInFunctionDeclaration": {
    "beforeOpeningRoundBrace": true,
    "beforeOpeningCurlyBrace": true
  },
  "requireSpacesInFunctionExpression": {
    "beforeOpeningRoundBrace": true,
    "beforeOpeningCurlyBrace": true
  },
  "requireSpacesInFunction": {
      "beforeOpeningRoundBrace": true,
      "beforeOpeningCurlyBrace": true
  },
  "requireSpacesInNamedFunctionExpression": {
      "beforeOpeningRoundBrace": true,
      "beforeOpeningCurlyBrace": true
  },
  "requireSpaceBeforeObjectValues": true,
  "requireSpaceBetweenArguments": true,
  "requireSpacesInConditionalExpression": {
    "afterTest": true,
    "beforeConsequent": true,
    "afterConsequent": true,
    "beforeAlternate": true
  },
  "requireSpacesInAnonymousFunctionExpression": {
    "beforeOpeningRoundBrace": true,
    "beforeOpeningCurlyBrace": true
  },
  "requireSpacesInsideObjectBrackets": "all",
  "requireSpacesInForStatement": true,
  "maximumLineLength": 120,
  "esnext": true,
  "fileExtensions": [".js", ".jsx"],
  "excludeFiles": ["node_modules/**"]
}

Supports jsx too. Requires npm i babel-jscs to lint ES6 and JSX properly.