no-negated-condition

✅ The extends: 'recommended' property in a configuration file enables this rule.

🔧 The --fix option on the command line can automatically fix some of the problems reported by this rule.

Negated conditions can be hard to reason about and require additional nesting/parenthesis around the condition:

Negated conditions can often be avoided or simplified by:

Flipping {{if (not condition)}} {{prop1}} {{else}} {{prop2}} {{/if}} to {{if condition}} {{prop2}} {{else}} {{prop1}} {{/if}}
Replacing if (not condition) with unless condition
Replacing unless (not condition) with if condition

Examples

This rule forbids the following:

{{#if (not condition)}}
  ...
{{/if}}

{{#if (not condition)}}
  ...
{{else}}
  ...
{{/if}}

{{#unless (not condition)}}
  ...
{{/unless}}

And similar examples with non-block forms like:

<img class={{if (not condition) "some-class" "other-class"}}>

{{input class=(if (not condition) "some-class" "other-class")}}

This rule allows the following:

{{#if condition}}
  ...
{{/if}}

{{#if condition}}
  ...
{{else}}
  ...
{{/if}}

{{#unless condition}}
  ...
{{/unless}}

And similar examples with non-block forms like:

<img class={{if condition "some-class" "other-class"}}>

{{input class=(if condition "some-class" "other-class")}}

The following values are valid configuration:

boolean -- true for enabled / false for disabled
object --
- simplifyHelpers -- boolean - whether to flag and autofix negated helpers like (not (eq ...)) or (not (gt ...)) that can be simplified (default true)