@putout/plugin-simplify-logical-expressions

The logical NOT (!) operator takes truth to falsity and vice versa.

(c) MDN

????Putout plugin adds ability to simplify logical expressions containing comparisons which will always evaluate to true or false since it's likely indications of programmer error. Complements @putout/plugin-apply-comparison-order. Merged to @putout/plugin-logical-expressions.

Install

npm i @putout/plugin-simplify-logical-expressions -D

{
    "rules": {
        "simplify-logical-expressions": "on"
    }
}

const is = !(options && !options.bidirectional);

if (!left.type === 'UnaryExpression');

const oneOf = a || a;
const same = a === a;

const is = !options || options.bidirectional;

if (left.type !== 'UnaryExpression');

const oneOf = a;
const same = true;

The rule also simplify duplication use:

-if (a && b || a && c) {
+if (a && (b || c)) {
}

Wrong cases with instanceof:

-!a instanceof b;
-a instanceof !b;
-!a instanceof !b;
+!(a instanceof b);

Wrong cases with in:

-!a in b;
-a in !b;
+!(a in b);

In case of duplicates:

-a && b && a
+a && b

Linter	Rule	Fix
???? Putout	`simplify-logical-expressions`	✅
⏣ ESLint	`no-constant-binary-expression`	❌