GlobalFunctionsisNaNbeginner

isNaN — NaN input

📖 Usage Example

isNaN(NaN)     // → true
typeof NaN     // → 'number'  (quirk!)

isNaN() returns true when its argument is NaN or coerces to NaN.

isNaN

isNaN(NaN) returns true.

Challenge: Verify that isNaN(NaN) === true.

💡 Hints (1)

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