no-invalid-this error is suppressed in node environment

[mhipszki]

The version of ESLint you are using (run eslint -v)

1.5.1

What you did (the source code and ESLint configuration)

source code

// some Node.js module's code
'use strict';

this.a = 3;

eslint config

{
    "extends": "eslint:recommended",
    "env": { "node": true },
    "rules": {
        "no-invalid-this": 2
    }
}

The actual ESLint output complete with numbers

nothing

What you expected to happen instead

Expected ESLint to report no-invalid-this error, but instead got nothing.

this refers to the module object itself in a context of a Node module, so it won't be undefined in any case.

However I would not encourage developers to use this.a = 3; in Node modules instead of exports.a = 3; as the latter one is more explicit, however it might be just my personal preference?

Node modules are cached after loading, which actually advocating the "singleton pattern" in a way, and again it might be my own preference, but I would not encourage developers to do that as a habit.

See https://nodejs.org/api/modules.html#modules_caching

Proposal: an option to warn developers not to use this in Node modules' root scope.

[eslintbot]

Thanks for the issue! 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

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[michaelficarra]

This is simply a bug in no-invalid-this. It should report top-level this, but is likely getting tripped up by the implicit top-level function wrapper in node programs.

[mysticatea]

Thanks for the report.
It's a bug of no-invalid-this.
I will fix it.