I have practiced Javascript for a long long time,
and there's always a contradiction, which has confused me so much.
That is, why NaN and Infinity are both types of “number”?
In mathematics,“Infinity”is just a concept, not a number.
“NaN”means“Not a number”on its literal meaning.
Obviously those are not“numbers.”
However, in Javascript, both“NaN”and“Infinity”are“number.”
You can try it like below:
typeof NaN // Returns“number”
typeof Infinity // Returns“number”
So what's the reason?
Could someone tell me the reason about this weird contradiction?

不然你覺得是什麼type?實作上來說這些只是特別的數字，可參考IEEE754

NaN is number type, and NaN != NaN

白馬是馬，白馬也非馬，就這個意思

樓上不如講 色即是空，空即是色

就像 '' 也是 string 啊，明明就是空的東西

浮點數裡有定義 NaN ，所以在 C 裡也能用。

null 也是 object 阿