Update: Check computed property keys in no-extra-parens

[mdjermanovic]

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

[X] Bug fix

Tell us about your environment

• ESLint Version: 6.0.1
• 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: 6,
  },
  rules: {
    "no-extra-parens": "error"
  }
};

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

const obj = {
  *[(Symbol.iterator)]() {}
}

const { [(a)]:b } = {}

What did you expect to happen?

2 errors.

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

No errors.

What changes did you make? (Give an overview)

Added the Property handler to no-extra-parens, to check computed property keys.

This affects both ObjectExpression properties and ObjectPattern properties.

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

• I guess this is a bug fix that adds more reported warnings, rather than a new behavior.
• The same check could be done within ObjectExpression and ObjectPattern handlers instead of the Property handler. I'm not sure which way would be better. ObjectExpression is already checking values.
• const a = { [b, c]: 1 } is indeed a syntax error without parens around the sequence expression.
• There will be a separate PR for classes.

[platinumazure]

LGTM, thanks!

I would be okay with merging this as is, but I'll ask this: Do you want to add a couple of test cases with a mix of unnecessary and necessary parentheses, and show that only the unnecessary parentheses are removed?

[platinumazure]

LGTM, thanks! Nice test coverage!

[g-plane]

LGTM, thanks!