comma-style rule fails on parenthesized array item

What version of ESLint are you using? eslint@2.8.0

What parser (default, Babel-ESLint, etc.) are you using? "parser": "babel-eslint",

Please show your full configuration:

{
  "extends": "eslint-config-airbnb",
  "env": {
    "browser": true,
    "node": true,
    "mocha": true
  },
  "parser": "babel-eslint",
  "rules": {
    //
    // Safety
    //
    "no-unused-vars": 1,
    // Do not allow `alert` calls.
    "no-alert": 1,
    // Use the `eslint-disable-line no-console` comment for intentional console statements.
    "no-console": 1,
    // The `no-use-before-define` prevents variable and function use before definition.
    "no-use-before-define": 1,
    // The `no-var` enforces `const` and `let`.
    "no-var": 1,
    // The `block-scoped-var` warns about possibly invalid logic when `var` is declared in a block scope and used outside. We prefer `const` and `let` over `var` but keep this for now.
    "block-scoped-var": 1,
    // Disable `guard-for-in` because we use `Object.keys().forEach` and do not have to extend `Object.prototype` for older browsers.
    "guard-for-in": 0,
    // Disable `no-shadow` and `no-param-reassign` to avoid useless renaming. Be careful.
    "no-shadow": 0,
    "no-param-reassign": 0,

    //
    // Coding style
    //
    "indent": [ 1, 2, { "SwitchCase": 1 } ],
    "padded-blocks": 0,
    // The `spaced-comment` warns about the commented-out source code and dirty comments.
    "spaced-comment": 1,
    // The `comma-dangle` helps to keep version control clean if array or object items are added or removed - only the lines that are actually changed will be highlighted.
    "comma-dangle": 0,
    "space-in-parens": 0,
    // TODO(sompylasar): Re-enable `curly` and fix.
    "curly": [ 0, "all" ],
    "array-bracket-spacing": [ 1, "always" ],
    "object-curly-spacing": [ 1, "always" ],
    "computed-property-spacing": 0,
    "brace-style": [ 1, "stroustrup", { "allowSingleLine": true } ],
    "no-trailing-spaces": [ 1, { "skipBlankLines": true } ],
    "linebreak-style": [ 1, "unix" ],
    "no-multiple-empty-lines": [ 1, { "max": 3, "maxEOF": 1 } ],
    "eol-last": [ 2, "unix" ],
    "id-length": [ 1, { "min": 2, "exceptions": [ "_", "$", "i", "j", "k", "x", "y", "e" ] } ],
    "camelcase": 1,
    "func-names": 1,
    "keyword-spacing": 1,
    "space-before-blocks": 1,
    "space-before-function-paren": [ 1, { "anonymous": "always", "named": "never" } ],
    "quotes": [ 1, "single", "avoid-escape" ],
    "no-multi-spaces": [ 1, { "exceptions": { "VariableDeclarator": true, "ImportDeclaration": true } } ],
    "dot-notation": 0,
    "prefer-template": 0,
    "max-len": [ 1, 250, 4, { "ignoreComments": true } ],
    "arrow-body-style": 0,
    "object-shorthand": 0,
    "no-case-declarations": 1,

    //
    // React:
    //
    "react/prop-types": 1,
    "react/jsx-uses-react": 2,
    "react/jsx-uses-vars": 2,
    "react/react-in-jsx-scope": 2,
    "react/jsx-quotes": 0,
    "react/no-multi-comp": 0,
    "react/sort-comp": 0,
    "react/jsx-closing-bracket-location": 1,
    "react/prefer-stateless-function": 1,
    "react/jsx-space-before-closing": 1,
    "jsx-quotes": 2,
    "jsx-a11y/img-uses-alt": 0,

    //
    // ES6:
    //
    "import/default": 0,
    "import/no-duplicates": 0,
    "import/named": 0,
    "import/namespace": 0,
    "import/no-unresolved": 0,
    "import/no-named-as-default": 2,
  },
  "plugins": [
    "react",
    "import"
  ],
  "settings": {
    "import/ignore": [
      "node_modules",
      "\\.(scss|less|css)$"
    ],
    "import/resolver": {
      "webpack": {
        "config": "./webpack/configForEslintImportResolver.js"
      }
    }
  },
  "globals": {
    "__DEVELOPMENT__": true,
    "__SERVER__": true,
    "__SERVER_DEVTOOLS__": true,
    "__SERVER_DISABLE_SERVERSIDE_RENDERING__": true,
    "__CLIENT__": true,
    "__CLIENT_DEVTOOLS__": true,
    "__LOCALHOST__": true,
    "__FAST_DEVELOPMENT__": true
  }
}

What did you do? Please include the actual source code causing the issue.

// snippet 1
const def = {};
const abc = [
  (''
  ),
  def,
];
def.abc = abc;

// snippet 2
const def = {};
const abc = [
  (''),
  def,
];
def.abc = abc;

// snippet 3
const def = {};
const abc = [
  '',
  def,
];
  def.abc = abc;

// snippet 4
const def = {};
const abc = {
  x: (''
  ),
  def,
};
def.abc = abc;

What did you expect to happen? Validation passes on all 4 snippets.

What actually happened? Please include the actual, raw output from ESLint.

// snippet 1
const def = {};
const abc = [
  (''
  ),  // error: Bad line breaking before and after ','. (comma-style)
  def,
];
def.abc = abc;

Other snippets pass.

[kaicataldo]

@sompylasar Thanks!

I’ve confirmed this also happens with the default parser. Checking it out locally, it seems that the closing parens is not taken into account in snippet 1, but IS in snippet 4. This seems like a bug to me.

More specifically in snippet 1 in the original post, previousItemToken is the empty string on line 4 at this point. However, in the case of snippet 4, previousItemToken is the closing parens.

[kaicataldo]

Any chance you can run ESLint on your files from the command line and share the output/confirm you’re getting the same errors?