Complex Async Arrow Throws Parser Error

Environment Information

Node / Yarn Versions:

$ node --version
v6.11.4
$ yarn --version
1.3.2

ESLint Package Versions:

{
    "babel-eslint": "^8.0.2",
    "eslint": "^4.3.0",
    "eslint-config-airbnb": "^15.1.0",
    "eslint-import-resolver-node": "^0.3.1",
    "eslint-plugin-dependencies": "^2.4.0",
    "eslint-plugin-import": "^2.7.0",
    "eslint-plugin-jsx-a11y": "^5.1.1",
    "eslint-plugin-react": "^7.1.0"
}

Configuration

{
  "extends": "airbnb",
  "plugins": [
    "dependencies"
  ],
  "settings": {
    "import/resolver": {
      "node": {
        "moduleDirectory": [
          "client",
          "node_modules"
        ]
      }
    }
  },
  "parserOptions": {
    "ecmaVersion": 6,
    "sourceType": "module",
    "ecmaFeatures": {
      "jsx": true,
      "experimentalObjectRestSpread": true
    }
  },
  "rules": {
    "comma-dangle": ["error", "never"],
    "semi": ["error", "always"],
    "react/jsx-filename-extension": 0,
    "react/prop-types": 0,
    "react/no-find-dom-node": 0,
    "jsx-a11y/label-has-for": 0,
    "jsx-a11y/href-no-hash": 0,
    "dependencies/no-cycles": 1
  },
  "globals": {
    "document": true,
    "window": true
  },
  "env": {
    "jest": true
  }
}

Issue Details

const reducer = async (state = initialState, action) => {
  const { payload } = action;
  switch (action.type) {
  // ...
};

Specifically, the errors that are thrown are via the import module; rules no-named-as-default and no-named-as-default-member introduce Parse errors when attempting to validate.

   8:63  error    Parse errors in imported module './Path/pathReducer': Unexpected token => (18:54)  import/no-named-as-default
   8:63  error    Parse errors in imported module './Path/pathReducer': Unexpected token => (18:54)  import/no-named-as-default-member

Unfortunately this is entirely valid syntax. I’m not quite sure why this isn’t working.

After further investigation, it seems as though the eslint’s parser is interpreting async ( //... as a function call, not as a function declaration modifier construct; it’s as if it’s favoring the following code (which is entirely invalid):

const reducer = async(state = initialState, action); // => {

[not-an-aardvark]

The issue is that you’re using ecmaVersion: 6 in your configuration, and async functions were only added in ECMAScript 2017. To fix this, you should update your config:

  "parserOptions": {
-    "ecmaVersion": 6,
+    "ecmaVersion": 2017,
    "sourceType": "module",
    "ecmaFeatures": {
      "jsx": true,
      "experimentalObjectRestSpread": true
    }
  },

[ikhsanalatsary]

exports.readAllNotification = async (req, res) => {
  try {
    await Notifications.update();
    ....
  } catch (e) {
    ....
  }
}

my eslintrc:

{
  "parserOptions": {
    "ecmaVersion": 2017,
    "sourceType": "module",
    "ecmaFeatures": {
      "arrowFunctions": true,
      "blockBindings": true,
      "classes": true,
      "defaultParams": true,
      "destructuring": true,
      "experimentalObjectRestSpread": true,
      "forOf": true,
      "generators": true,
      "modules": true,
      "objectLiteralComputedProperties": true,
      "objectLiteralDuplicateProperties": false,
      "objectLiteralShorthandMethods": true,
      "objectLiteralShorthandProperties": true,
      "spread": true,
      "superInFunctions": true,
      "templateStrings": true,
      "jsx": true
    }
  },
  "extends": [
    "standard",
    "eslint:recommended",
    "plugin:node/recommended"
  ],
  "rules": {
    "camelcase": 0,
    "comma-dangle": [ 0, "always-multiline"],
    "comma-spacing": [2, { "before": false, "after": true }],
    "consistent-return": 0,
    "curly": 0,
    "default-case": 0,
    "eqeqeq": [2, "smart"],
    "func-names": 0,
    "guard-for-in": 2,
    "indent": [2, 2, { "SwitchCase": 1 }],
    "key-spacing": [2, { "beforeColon": false, "afterColon": true }],
    "keyword-spacing": [2, { "before": true, "after": true }],
    "max-len": 0,
    "new-cap": [2, { "newIsCapExceptions": ["acl.memoryBackend", "acl"] }],
    "no-bitwise": 0,
    "no-caller": 2,
    "no-console": 0,
    "no-else-return": 0,
    "no-empty-class": 0,
    "no-multi-spaces": 2,
    "no-param-reassign": 0,
    "no-shadow": 0,
    "no-spaced-func": 2,
    "no-throw-literal": 2,
    "no-trailing-spaces": 2,
    "no-undef": 2,
    "no-unneeded-ternary": 2,
    "no-unreachable": 2,
    "no-underscore-dangle": 0,
    "no-unused-expressions": 0,
    "no-unused-vars": 0,
    "no-use-before-define": [1, "nofunc"],
    "no-var": 0,
    "object-curly-spacing": [2, "always"],
    "one-var": [0, "never"],
    "one-var-declaration-per-line": [2, "always"],
    "padded-blocks": 0,
    "space-before-function-paren": 0,
    "space-in-parens": [2, "never"],
    "spaced-comment": [2, "always"],
    "strict": 0,
    "quote-props": 0,
    "quotes": [1, "single"],
    "wrap-iife": [2, "outside"],
    "vars-on-top": 0,
    "async-await/space-after-async": 2,
    "async-await/space-after-await": 2
  },
  "env": {
    "es6": true,
    "node": true,
    "mocha": true,
    "commonjs": true
  },
  "globals": {
    "by": true,
    "io": true,
    "Promise": true,
    "__TESTING__": true,
    "_": false,
    "ApplicationConfiguration": true
  },
  "plugins": ["node", "async-await"]
}

deps: “eslint”: “4.15.0”, “eslint-config-standard”: “11.0.0-beta.0”, “eslint-plugin-async-await”: “0.0.0”, “eslint-plugin-import”: “2.8.0”, “eslint-plugin-node”: “5.2.1”, “eslint-plugin-promise”: “3.6.0”, “eslint-plugin-standard”: “3.0.1”,