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noGlobalIsNan (since v1.0.0)

Diagnostic Category: lint/suspicious/noGlobalIsNan

Use Number.isNaN instead of global isNaN.

Number.isNaN() and isNaN() do not have the same behavior. When the argument to isNaN() is not a number, the value is first coerced to a number. Number.isNaN() does not perform this coercion. Therefore, it is a more reliable way to test whether a value is NaN.

Examples

Section titled Examples

Invalid

Section titled Invalid
isNaN({}); // true
suspicious/noGlobalIsNan.js:1:1 lint/suspicious/noGlobalIsNan  FIXABLE  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━

  ✖ isNaN is unsafe. It attempts a type coercion. Use Number.isNaN instead.
  
  > 1 │ isNaN({}); // true
      │ ^^^^^
    2 │ 
  
  ℹ See the MDN documentation for more details.
  
  ℹ Unsafe fix: Use Number.isNaN instead.
  
    1   │ - isNaN({});·//·true
      1 │ + Number.isNaN({});·//·true
    2 2 │

Valid

Section titled Valid
Number.isNaN({}); // false
Section titled Related links