Update: Check empty string property names in sort-keys

[mdjermanovic]

What is the purpose of this pull request? (put an "X" next to item)

[X] Bug fix

This is a small bug fix, but it can produce more warnings.

Tell us about your environment

• ESLint Version: 6.1.0
• Node Version: 10.16.0
• npm Version: 6.9.0

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

default

Please show your full configuration:

Configuration

module.exports = {
  parserOptions: {
    ecmaVersion: 2015,
  },
};

What did you do? Please include the actual source code causing the issue.

/*eslint sort-keys: "error"*/

const obj = {
  "a": 1,
  "": 2
}

What did you expect to happen?

1 error

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

No errors.

What changes did you make? (Give an overview)

getStaticPropertyName() return value is now explicitly compared to null, because it can be a valid empty string value.

Is there anything you'd like reviewers to focus on?

[aladdin-add]

LGTM, thanks a lot! I never bethought such a case🤣, maybe it also happens in other similar rules.

[aladdin-add]

I'd suggest it to be a bugfix(tagged "Fix"), let's see other members thoughts. 😄

[mdjermanovic]

LGTM, thanks a lot! I never bethought such a case, maybe it also happens in other similar rules.

14 rules are using getStaticPropertyName() at the moment. #12069 should fix no-dupe-keys, #12071 yoda.

The remaining rules are either handling this edge case, or it doesn't affect them (at least I think so, might be worth checking).

Re the tag, I guess it should be 'Update' because the bug fix produces more warnings?

[platinumazure]

@aladdin-add

I'd suggest it to be a bugfix(tagged "Fix"), let's see other members thoughts. 😄

We want to have bugfixes that report more warnings be semver-minor, so we ask contributors to use the Update tag in this case. So the tag is correct here.

[kaicataldo]

LGTM. Thanks for including a comprehensive test suite!

[platinumazure]

Merged. Thanks for contributing!