⏎ Lint Rules

noUnsafeNegation (since v0.7.0)

This rule is recommended by Rome.

Disallow using unsafe negation.

Examples

Invalid

!1 in [1,2];

correctness/noUnsafeNegation.js:1:1 lint/correctness/noUnsafeNegation  FIXABLE  ━━━━━━━━━━━━━━━━━━━━

  ✖ The negation operator is used unsafely on the left side of this binary expression.
  
  > 1 │ !1 in [1,2];
      │ ^^^^^^^^^^^
    2 │ 
  
  ℹ Suggested fix: Wrap the expression with a parenthesis
  
    1 │ !(1·in·[1,2]);
      │  +          + 

/**test*/!/** test*/1 instanceof [1,2];

correctness/noUnsafeNegation.js:1:10 lint/correctness/noUnsafeNegation  FIXABLE  ━━━━━━━━━━━━━━━━━━━

  ✖ The negation operator is used unsafely on the left side of this binary expression.
  
  > 1 │ /**test*/!/** test*/1 instanceof [1,2];
      │          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    2 │ 
  
  ℹ Suggested fix: Wrap the expression with a parenthesis
  
    1 │ /**test*/!/**·test*/(1·instanceof·[1,2]);
      │                     +                  + 

Valid

-1 in [1,2];
~1 in [1,2];
typeof 1 in [1,2];
void 1 in [1,2];
delete 1 in [1,2];
+1 instanceof [1,2];