Fix: Handle empty string property names in getFunctionNameWithKind

[mdjermanovic]

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

[X] Bug fix

Minor fix in astUtils.getFunctionNameWithKind() for empty string property names, to show '' instead of nothing in warning messages.

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: 2018,
  },
};

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

An example:

/*eslint require-await: "error"*/

(class { async ''() { doSomething() } })

What did you expect to happen?

  3:10  error  Async method '' has no 'await' expression  require-await

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

  3:10  error  Async method has no 'await' expression  require-await

What changes did you make? (Give an overview)

Explicitly check for null.

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

[platinumazure]

LGTM so far, thanks for contributing!

Just out of curiosity, what happens with 0 or '0'? Is that affected by your change?

[mdjermanovic]

Just out of curiosity, what happens with 0 or '0'? Is that affected by your change?

It shouldn't be affected because getStaticPropertyName() should return a string which would be a truthy "0" in both cases.

But to be sure that getStaticPropertyName() doesn't have the same small bug, I tried in Demo and it works well already (Async method '0' has no 'await' expression)

[kaicataldo]

LGTM. Thanks for contributing!