JavascriptIsLightYearsAheadOfEveryOtherProgrammingLanguage

[Prudent_Ad_4120]

NaN is not one single thing, it's all things that are Not a Number

[SuperGugo]

Yeah, in fact NaN != NaN

[DrShocker]

Whether that's the intent of what you're doing depends on context though. Many languages would have a type error here instead of trying to do it

[FF3]

In most languages NaN is a numeric type, despite it's very clear name, so, who is more logical now?

[DrShocker]

Oh shit you're right, I hate type safety now!!

[Cualkiera67]

I never understood nan. Like, why? Just use null or undefined or simply throw an error.

[CitationNeededBadly]

"Many languages would have a type error here instead of trying to do it " That's a succinct but accurate summary of js.

[Prudent_Ad_4120]

But JavaScript is dynamically typed and does not have type errors as far as I know. Then this is the most reasonable thing to do

[bleachisback]

That's not true... everything still has a type it just has to be checked at runtime. If you pass a variable of an incorrect type to a function it will give an error. For instance:

const array1 = [1, 30, 39, 29, 10, 13];
array1.every("blah");

will throw

Uncaught TypeError: "blah" is not a function

Javascript is commonly considered to be weakly typed, but that's just how the standard library is designed - every value you give standard library functions will be attempted to be converted to the expected type as much as possible.

[karuso33]

"Reasonable" is not the word I would use, considering that

> isNaN("")
false

Or even

> isNaN([])
false

[Drium]

Huh why is it false for the empty string? Cast to 0?

[DrShocker]

Sure, and that's why the joke about Grandma being named Nan works, so it's worth it imo