Promise' is not defined. (no-undef)

[bharathvaj-ganesan]

• ESLint Version: 4.14.0
• Node Version: 6.11.1
• npm Version: 5.3.0

What parser (default, Babel-ESLint, etc.) are you using?
default

const promise = new Promise((resolve, reject) => {});

eslint config

{
	"env": {
		"browser": true,
		"node": true
	},
	"parserOptions": {
		"ecmaVersion": 6,
		"sourceType": "script"
	},
	"extends": ["kentcdodds/possible-errors", "kentcdodds/best-practices"],
	"rules": {
		"global-require": "off"
	}
}

What did you expect to happen?
No un-def error for es6 globals (Promise)

What actually happened?
Throws un-def error for 'Promise'

[eslint-deprecated]

Hi @bharathvaj1995, thanks for the issue. It looks like there's not enough information for us to know how to help you.

If you're reporting a bug, please be sure to include:

1. The version of ESLint you are using (run eslint -v)
2. What you did (the source code and ESLint configuration)
3. The actual ESLint output complete with numbers
4. What you expected to happen instead

Requesting a new rule? Please see Proposing a New Rule for instructions.

Requesting a rule change? Please see Proposing a Rule Change for instructions.

If it's something else, please just provide as much additional information as possible. Thanks!

(edited for emphasis by platinumazure)

[j-f1]

Do you have es6: true set under the env key in your ESLint config?

[bharathvaj-ganesan]

@j-f1 I have updated the issue with my .eslintrc config. Yes, i have.

[j-f1]

@bharathvaj1995 It looks like you only have browser and node set in your env setting. Can you try adding "es6": true there, too?

[bharathvaj-ganesan]

@j-f1 It solved the issue thanks, but how is it differs from ecmaVersion inside parserOptions ? I don't get it because es6 syntax different from es6 globals ?

[platinumazure]

@bharathvaj1995 ecmaVersion only affects the parser, so it allows ES6 syntax (such as let/const). The environment will set ecmaVersion for you, but will also enable all of the ES6 globals (such as Promise, Map, Set). If you want ES7 (or later) and ES6 globals, you would do env es6:true and ecmaVersion: (something greater than 6)... Hope that makes sense!

[rugk]

Maybe change the doc, so it is clear "ecmaVersion" does not imply "es6" globals.

So the position in the doc:

https://eslint.org/docs/user-guide/configuring#specifying-environments

Maybe change it to:

es6 - enable all ECMAScript 6 features except for modules (this automatically sets the ecmaVersion parser option to 6, but not vice-versa).

[reks-scripts]

I agree with rugk. The documentation could use some clarification... I just got hung up on the exact same issue. I removed "es6": true from my config after reading the same line rugk pointed out assuming that parserOptions.ecmaVersion: 8 would override/include the es6 features and then some.

[not-an-aardvark]

Feel free to open a pull request if you think the documentation could be improved!