GlobalFunctionsisNaNintermediate

isNaN — non-numeric string coerces to NaN

📖 Usage Example

isNaN('hello')        // → true  (Number('hello') → NaN)
Number.isNaN('hello')  // → false (no coercion)

The global isNaN() coerces strings to numbers first — use Number.isNaN() to skip coercion.

isNaN with String

isNaN('hello') coerces the string to NaN and returns true.

Challenge: Verify the coercion.

💡 Hints (1)

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