Avoid negating the left operand of relational operators


ID: typescript-best-practices/no-unsafe-negation

Language: TypeScript

Severity: Warning

Category: Best Practices


Negation of the left-hand side of an expression is often unintended.

Non-Compliant Code Examples

!a in b
(!a in b)
!(a) in b
!a instanceof b
(!a instanceof b)
!(a) instanceof b

Compliant Code Examples

a in b
a in b === false
!(a in b);
(!a) in b
a instanceof b
a instanceof b === false;
!(a instanceof b);
(!a) instanceof b;
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