eslint/no-extra-boolean-cast Correctness
What it does
This rule disallows unnecessary boolean casts.
Why is this bad?
In contexts such as an if statement's test where the result of the expression will already be coerced to a Boolean, casting to a Boolean via double negation (!!) or a Boolean call is unnecessary.
Examples
Examples of incorrect code for this rule:
javascript
var foo = !!!bar;
var foo = Boolean(!!bar);
if (!!foo) {}
if (Boolean(foo)) {}
// with "enforceForLogicalOperands" option enabled
if (!!foo || bar) {}Examples of correct code for this rule:
javascript
var foo = !bar;
var foo = Boolean(bar);
if (foo) {}
if (foo) {}
// with "enforceForLogicalOperands" option enabled
if (foo || bar) {}Configuration
This rule accepts a configuration object with the following properties:
enforceForInnerExpressions
type: boolean
default: false
when set to true, in addition to checking default contexts, checks whether extra boolean casts are present in expressions whose result is used in a boolean context. See examples below. Default is false, meaning that this rule by default does not warn about extra booleans cast inside inner expressions.
How to use
To enable this rule in the CLI or using the config file, you can use:
bash
oxlint --deny no-extra-boolean-castjson
{
"rules": {
"no-extra-boolean-cast": "error"
}
}