JS Practice — Built-in Objects

Number.isNaN() — NaN !== NaN, use Number.isNaN instead

📖 Usage Example

// Check for NaN without coercion
Number.isNaN(NaN)    // → true
Number.isNaN('NaN')  // → false (no coercion)
Number.isNaN(42)     // → false

Use Number.isNaN() instead of the global isNaN() to check for NaN without coercing the argument first.

Why Not Use === for NaN?

NaN === NaN is false — you cannot use strict equality to check for NaN. Use Number.isNaN() instead.

💡 Hints (1)