Rule Request: prevent equality comparison with booleans

Please describe what the rule should do:

Disallow ==, ===, !=, and !== when one (or both) of the operands are true or false.

What category of rule is this? (place an “X” next to just one item)

[X] Enforces code style [ ] Warns about a potential error [ ] Suggests an alternate way of doing something [ ] Other (please specify:)

Provide 2-3 code examples that this rule will warn about:

x === true
false != x
true === true

Why should this rule be included in ESLint (instead of a plugin)?

This is an extremely basic style issue that has cropped up in just about every codebase I’ve ever worked in.

[not-an-aardvark]

Thanks for your interest in improving ESLint. Unfortunately, it looks like this issue didn’t get consensus from the team, so I’m closing it. We define consensus as having three 👍s from team members, as well as a team member willing to champion the proposal. This is a high bar by design – we can’t realistically accept and maintain every feature request in the long term, so we only accept feature requests which are useful enough that there is consensus among the team that they’re worth adding.

Since ESLint is pluggable and can load custom rules at runtime, the lack of consensus among the ESLint team doesn’t need to be a blocker for you using this in your project, if you’d find it useful. It just means that you would need to implement the rule yourself, rather than using a bundled rule that is packaged with ESLint.

[platinumazure]

Just add ^ and $ anchors and that should avoid strings containing. You could also try using left.raw instead of left.value, that might avoid false positives for “true”/“false” strings. Sorry for the mix-up.

On Dec 21, 2017 11:40 AM, “Luke M Willis” [e-mail] wrote:

@platinumazure https://github.com/platinumazure I set up that rule, slightly modified to account for true and false:

“no-restricted-syntax”: [ “error”, { “selector”: “BinaryExpression[operator=/(==|===|!=|!==)/][left.value=/(true|false)/], BinaryExpression[operator=/(==|===|!=|!==)/][right.value=/(true|false)/]”, “message”: “Don’t compare for equality against boolean literals” } ]

This catches all the issues, but also captures x === ‘true’ and “the value is false” != x.

I could probably write a regex that excluded strings, but that would be pretty fragile.

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/eslint/eslint/issues/9743#issuecomment-353412274, or mute the thread https://github.com/notifications/unsubscribe-auth/AARWet6JFYCDc035cP7_Rc7IrmwZ07kgks5tCpgcgaJpZM4RIy_s .