NaN == NaN // false NaN === NaN // false Object.is(NaN, NaN) // true Number.isNaN(NaN) // true typeof NaN // number
Because NaN is number type, so there is only one NaN.
[Javascript] NaN is number type and NaN === NaN is false
原文：https://www.cnblogs.com/Answer1215/p/12543862.html