Skip to content

Latest commit

 

History

History
17 lines (11 loc) · 715 Bytes

Tricky-Question-1.md

File metadata and controls

17 lines (11 loc) · 715 Bytes

Question. For which value of x the results of the following statements are not the same?

if( x <= 100 ) {...}
if( !(x > 100) ) {...}
Answer

NaN <= 100 is false and NaN > 100 is also false, so if the value of x is NaN, the statements are not the same.

The same holds true for any value of x that being converted to type Number, returns NaN, e.g.: undefined, [1,2,5], {a:22} , etc.

This is why you need to pay attention when you deal with numeric variables. NaN can’t be equal, less than or more than any other numeric value, so the only reliable way to check if the value is NaN, is to use the isNaN() function.