Fix: account for linebreaks before postfix ++/-- in no-extra-parens

[mdjermanovic]

Prerequisites checklist

• I have read the contributing guidelines.

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

[ ] Documentation update
[X] Bug fix (template)
[ ] New rule (template)
[ ] Changes an existing rule (template)
[ ] Add autofixing to a rule
[ ] Add a CLI option
[ ] Add something to the core
[ ] Other, please explain:

Tell us about your environment

• ESLint Version: v7.10.0
• Node Version: v12.18.4
• npm Version: v6.14.6

What parser (default, @babel/eslint-parser, @typescript-eslint/parser, 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.

Online Demo

/* eslint no-extra-parens: "error" */

(a
)++

What did you expect to happen?

No errors. Per the specification for UpdateExpression, linebreaks are not allowed before postfix ++ and --. In similar situations (return, throw, yield) no-extra-parens doesn't report an error.

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

no-extra-parens error and auto-fix to:

/* eslint no-extra-parens: "error" */

a
++

Message after the auto-fix:

  5:1  error  Parsing error: Unexpected token

What changes did you make? (Give an overview)

Fixed the no-extra-parens rule to not report an error if the parenthesized argument of an UpdateExpression is not on the same line as the postfix operator.

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

[yeonjuan]

LGTM!