eslint ignores variables named `status`

[sidoshi]

Can you reproduce the problem with latest npm?

yes. npm version: 4.1.1

Description

Linter ignores status variable name when checking for unused vars.
Not sure if this is a bug or expected behaviour.

Expected behavior

It should probably warn when I have not declared a variable named status and have this line of code:
console.log(status)

Actual behavior

Even though I have not declared any variable named status,
using it does not show any warning or errors.
it shows no-undef error on all other variables names like statuss as expected

Environment

Run these commands in the project folder and fill in their results:

1. npm ls react-scripts (if you haven’t ejected): 0.9.0
2. node -v: v7.7.1
3. npm -v: 4.4.1

Then, specify:

1. Operating system: Linux, Deepin
2. Browser and version: any

Reproducible Demo

create a new app with:
create-react-app test-app
In index.js type: console.log(status)
It won't show any error that status is not defined but changing the variable name to statuss would show error as expected

[n3tr]

As I understand it is expected behavior since status is a window property (https://developer.mozilla.org/en-US/docs/Web/API/Window/status) and we configure eslint env. browser on eslint-config-react-app/index.js#L29

[gaearon]

It's still confusing and IMO we should forbid implicit window properties without window. qualifier.

[sidoshi]

I think eslint doesn't support that.
See eslint/eslint#3959 .
It seems like we would have to remove browser env and add a list of some variables to globals like localStorage.

[gaearon]

I don't mind having our own list of globals.

[sidoshi]

I can work on this.

[gaearon]

Sounds good!

[sidoshi]

see #1840

[gaearon]

I think I was wrong about this. People are genuinely confused when “valid” globals don’t work—especially if they’re built into the browser.

I propose another strategy. Let’s go through the list of globals and pick a list of names that can genuinely be confused with local variables (e.g. status is a great candidate). It’s gonna be subjective but I’m okay with that.

[gaearon]

Fixed by #2130 with an explicit blacklist.