(Greasemonkey 4.0) error 'GM' is not defined [ESLint]

[darkred]

Continuation from eslint/eslint#9621 (comment) :

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Tell us about your environment

• ESLint Version: 4.11.0
• Node Version: 9.1.0 x64
• npm Version: 5.5.1

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

Please show your full configuration:

Configuration

module.exports = {
    "env": {
        "browser": true,
		"greasemonkey": true,
    },
	"extends": "eslint:recommended",
    "parserOptions": {      // see https://eslint.org/docs/user-guide/configuring
        "ecmaVersion": 8,
        "sourceType": "script",
        "ecmaFeatures": {
            "impliedStrict": true,
        }
    },
    "rules": {
        "semi": ["warn","always"],
    }
};

What did you do? Please include the actual source code causing the issue, as well as the command that you used to run ESLint.

// ==UserScript==
// @name     GM set/get demo
// @grant    GM.getValue
// @grant    GM.setValue
// ==/UserScript==

(async function() {
	let i = await GM.getValue('i', 0);
	GM.setValue('i', i + 1);
})();

eslint 1.js

What did you expect to happen?

No errors should be found.

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

It found the following 2 errors:

C:\Users\Kostas\Desktop\1.js
  8:16  error  'GM' is not defined  no-undef
  9:2   error  'GM' is not defined  no-undef

✖ 2 problems (2 errors, 0 warnings)

That's because, since Greasemonkey 4.0 :

There is only one object provided to user scripts now, named GM.
It has several properties. One of them is info – the equivalent of the old GM_info.
There are also several methods of this object:

• getResourceUrl,
• deleteValue,
• getValue,
• listValues,
• setValue,
• xmlHttpRequest.

To use these methods you still need @grant, and use the new name, e.g.:

 // @grant GM.setValue

The new form has a dot, where the old form has an underscore.
You may specify both @grants, if you'd like to be compatible with Greasemonkey 4 and other user script engines at the same time.
As of today, there is no support for:

• GM_log (use console.log),
• GM_addStyle,
• GM_registerMenuCommand, nor
• GM_getResourceText.

The complete list of the GM obect's properties is the following: (Greasemonkey_Manual:API)

• GM.info
• GM.deleteValue
• GM.getValue
• GM.listValues
• GM.setValue
• GM.getResourceUrl
• GM.openInTab
• GM.setClipboard
• GM.xmlHttpRequest, and
• unsafeWindow

In other words, the 'Greasemonkey' environment should be updated to include the GM object and its properties. (all the old GM_* grants should also be maintained, even the 4 currently not supported ones, for use by other script engines) .

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I also quote the reply by @platinumazure :

Our environment globals come from the globals repository. I think it would probably make more sense to file an issue there.

Looking at their main global data file, I see that the old properties are the only ones present

[sindresorhus]

Pull request welcome :)

[darkred]

@sindresorhus I hope it's ok.