JavaScript: NaN
NaN
is the value of the property key "NaN"
of
the Global Object.
console.log( Number.isNaN( window["NaN"] ) ); // true
NaN
is a literal value. For example, you can write let x = NaN;
NaN
means โNot a Numberโ. It is typically returned when converting a value to number that doesn't make sense.
// convert string to number // if arg does not make sense, result is NaN console.log( Number.isNaN( Number( "xyz") ) ); // true
[see Number Constructor]
Type of NaN
is "number"
.
console.log( typeof NaN === "number" ); // true
NaN === NaN
return false
.
console.log( NaN === NaN ); // false
To test equality of NaN
, use
Object.is
.
To test if a value is NaN
, use
Number.isNaN.