Does isNaN and NaN have a boolean

Question

I can't seem to understand why when I put in the console isNaN == true results to false while !isNaN == false returns to true.

When

NaN == true
false
NaN == false
false

Sorry I'm kinda new and somewhat confused.

[`isNaN`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/isNaN) is a function... while `NaN` never equals to anything. — Derek 朕會功夫, Feb 01 '17 at 05:29

score 1 · Answer 1 · answered Feb 01 '17 at 05:40

1

isNaN is a function which determines if the value is NaN. So isNaN will check if the input is a number or not .

For example isNaN(5) == true will return false , because 5 is a number, Simillarly for empty string isNaN('') == true will also return false it is not a number. But for isNaN('Hello') == true will return true, since 'Hello' is not a number

Now when using negation(!) it will work oppositely

answered Feb 01 '17 at 05:40

brk

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*Note:* `isNaN(true)` is `false`, same for `false` – vsync Dec 14 '19 at 23:00

score 0 · Accepted Answer · answered Feb 01 '17 at 05:32

0

The isNaN() function determines whether a value is NaN or not.

its return true if the given value is NaN; otherwise, false.

see below link for more info

answered Feb 01 '17 at 05:32

Darshak

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Wow Thanks! This helped alot! – icedev Feb 01 '17 at 05:33
@icedogedev if its helpful thn please correct and upvote my ans...plz – Darshak Feb 01 '17 at 05:34

Does isNaN and NaN have a boolean

2 Answers2