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by some-1 5021 days ago
No, the correct way is to use the global function isNaN(x);
1 comments

isNaN will return true for NaN and all values that coerce to it. The equals check will test ONLY for NaN itself:

var x = "a";

isNaN(x); // true

(x === x) === false // false

x = NaN

isNaN(x); // true

(x === x) === false // true