eslint: error Parsing error: The keyword 'const' is reserved

Question

I am getting this error from ESLint:

error  Parsing error: The keyword 'const' is reserved

from this code:

const express = require('express');
const app = express();
const _ = require('underscore');

I've tried removing node_modules and reinstalling all npm packages (as suggested here), but to no avail.

Answer 1

ESLint defaults to ES5 syntax-checking. You'll want to override to the latest well-supported version of JavaScript.

Try adding a .eslintrc file to your project. Inside it:

{
    "parserOptions": {
        "ecmaVersion": 2017
    },

    "env": {
        "es6": true
    }
}

Hopefully this helps.

EDIT: I also found this example .eslintrc which might help.

Answer 2

I used .eslintrc.js and I have added following code.

module.exports = {
    "parserOptions": {
        "ecmaVersion": 6
    }
};

Answer 3

you also can add this inline instead of config, just add it to the same file before you add your own disable stuff

/* eslint-env es6 */
/* eslint-disable no-console */

my case was disable a file and eslint-disable were not working for me alone

/* eslint-env es6 */
/* eslint-disable */

Answer 4

If using Visual Code one option is to add this to the settings.json file:

"eslint.options": {
    "useEslintrc": false,
    "parserOptions": {
        "ecmaVersion": 2017
    },
    "env": {
        "es6": true
    }
}

Answer 5

I had this same problem with this part of my code:

const newComment = {
    dishId: dishId,
    rating: rating,
    author: author,
    comment: comment
};
newComment.date = new Date().toISOString();

Same error, const is a reserved word.

The thing is, I made the .eslintrc.js from the link you gave in the update and still got the same error. Also, I get an parsing error in the .eslintrc.js: Unexpected token ':'.

Right in this part:

"env": {
"browser": true,
"node": true,
"es6": true
},

...

Answer 6

In my case, it was unable to find the .eslintrc file so I copied from node_modules/.bin to root.

Answer 7

Please use this syntax in this file .eslintrc.js. If it doesn't exist then you have to create one. Also, do look for steps on how to install eslint as a dev dependency to your current project first by writing these steps npm install --save-dev eslint then create .eslintrc.js file in the project root.

{
    "parserOptions": {
        "ecmaVersion": 2017
    },

    "env": {
        "es6": true
    }
}