there is a game / challenge for this
The beauty of JavaScript.
You probably haven’t encountered truthsy and falsy values yet?
this makes sense
NaN is a “this was meant to be a number but it somehow isnt”
I think this, and the fact that NaN == NaN is false, make perfect sense.
NaN is the result of mathematically undefined behavior. You’re not going to get a NaN outside of a number context, so tying it together in the Number scope is fine.Same reason NULL != NULL. It makes sense if you understand how these values work.
The result of mathematically undefined behaviour should be an error, but sure, go ahead and return Keleven. 1/0 = keleven fuck it.
NaN is one of the ways IEEE maths signals an erroneous calculation when the only outbound communication channel is the returned IEEE value. Reading the history and rationale of the floating-point standard will likely convince you this was and probably is a good compromise.
Because IEEE values often have hardware acceleration that is a significant factor in performance, languages rarely (if ever) choose to map all IEEE error values to language-specific error reporting (e.g. a thrown exception or error-tracking algebraic data type).
JS is hardly an outlier here.
I do think it probably violates the principle of least surprise, but I don’t think I understand the scale of “momentum” change that would need to take place across society (industry, academia, etc.) to align it with naive expectations.
NaN is a error and it’s your responsibility to handle it gracefully. No need to halt the entire program when you fuck up some maths.
NaN is a error
Error.isError(NaN) // Falsenan is a ieee754-defined error. what javascript calls errors these days (it tends to change a lot) has little to nothing to do with that. it’s on every developer to familiarise themself with ieee754, it’s one of the most important documents in the profession.
while nan is an invalid floating-point number, it is a valid value for a float-typed field. making it into an error is like adding a bit labelled “crash” to every number in your program.
please do everyone a favor and stop writing code.
No, it should not be an error. If you’re making a calculator and your user enters 1/0, your program should not have the propensity to crash; the result should simply be NaN and you should choose how you display that result to your user.
You talk like error handling isn’t a thing.
fun fact: getting NaN from a numeric calculation is the error that you handle. if this wasn’t obvious, please don’t write code for anyone but yourself. hope this helps.
NaNis a primitive value, not anError.>> typeof 1 / "a" "number"
https://www.destroyallsoftware.com/talks/wat is much better. This post is pretty low-effort.
I love that talk.
And yes, this post is low-effort, but so are most posts on here. Just a bunch of screenshots from various microblogging platforms reposted from Reddit.
It’s clearly bread.
Infinityis also a number in JavaScript / IEEE number formats, but you’ll get a lot of grumbling from mathematicians with that sort of assertion.Once you accept that each float represent a range of reals most design decisions make sense.
Infinity is just the name given to values that are too large to represent otherwise and negative zero includes negative values too close to zero.What mathematics probably hate most about floats is that rounding breaks commutativity.
What mathematics probably hate most about floats is that rounding breaks commutativity.
Actually, the maths people in my circles tend to complain more about how the normal floating-point equality test doesn’t define an equivalence relation, but really any of the violations of field properties can attract complaints.
The way I think about it: number is a js type. A floating point double, in other languages.
NaN is a state that a number type can be in, representing a situation where the outcome of the numeric operation cannot be determined.
Anywho, also yea ….JavaScript is goofy
