Why does isNaN (" ") (string with spaces) equal false?
In JavaScript, why does isNaN(" ") evaluate to false, but isNaN(" x") evaluate to true? I’m performing numerical operations on a text input field, and I’m checking if the field is null, "", or NaN. When …
Confusion between isNaN and Number.isNaN in javascript
Oct 16, 2015 · Answer: Due to both equality operators, == and ===, evaluating to false when checking if NaN is NaN, the function Number.isNaN() has become necessary. In comparison to the global …
How do you check that a number is NaN in JavaScript?
Apr 16, 2010 · var myVar = "A"; isNaN(Number(myVar)) It actually makes sense, because "A" is actually not a number. But what we really want to check is if myVar is exactly of value NaN. So isNaN () …
python - How to check for NaN values - Stack Overflow
While math.isnan and np.isnan will return True for NaN values, you cannot check for different type of objects like None or strings. Both methods will return an error, so checking a list with mixed types will …
What exactly does isNaN() do in javaScript? - Stack Overflow
Nov 11, 2015 · The isNaN function is not really intended as a general-purpose test for whether something is or is not a number. It's a test for the specific numeric value NaN. It's often used as a …
Why is isNaN (null) == false in JS? - Stack Overflow
Apr 23, 2015 · The function isNaN() can be used to answer this question, but semantically it's referring specifically to the value NaN. From Wikipedia for NaN: NaN (N ot a N umber) is a value of the …
Why does Number.isNaN () return false for Strings?
Jul 10, 2017 · Number.isNaN only returns true if its argument is NaN. It seems weird, but the reason for its existence is falsiness of NaN === NaN expression.
Is Number.IsNaN () more broken than isNaN () - Stack Overflow
Aug 7, 2014 · The reason isNaN() is "broken" is because, ostensibly, type conversions aren't supposed to happen when testing values. That is the issue Number.isNaN() is designed to address. In …
Why check for !isNaN () after isFinite ()? - Stack Overflow
goog.math.isFiniteNumber = function(num) { return isFinite(num) && !isNaN(num); }; So, first it checks whether the number is finite using the native isFinite function, and then does an additional check to …
JavaScript function, if else, isNaN - Stack Overflow
Apr 6, 2014 · The isNaN () is a JavaScript function. It returns true if the given value is (NaN).