O método Number.isNaN()
determina se o valor passado é NaN
. Esta é uma versão mais robusta que isNaN()
.
Sintaxe
Number.isNaN(valor)
Parâmetros
valor
- O valor a ser testado se é
NaN
.
Descrição
Due to both equality operators, ==
and ===
, evaluating to false
when checking if NaN
is NaN
, the function Number.isNaN()
has become necessary. This situation is unlike all other possible value comparisons in JavaScript.
In comparison to the global isNaN()
function, Number.isNaN()
doesn't suffer the problem of forcefully converting the parameter to a number. This means it is now safe to pass values that would normally convert to NaN
, but aren't actually the same value as NaN
. This also means that only values of the type number, that are also NaN
, return true
.
Exemplos
Number.isNaN(NaN); // true
Number.isNaN(Number.NaN); // true
Number.isNaN(0 / 0) // true
// e.g. these would have been true with global isNaN()
Number.isNaN("NaN"); // false
Number.isNaN(undefined); // false
Number.isNaN({}); // false
Number.isNaN("blabla"); // false
// These all return false
Number.isNaN(true);
Number.isNaN(null);
Number.isNaN(37);
Number.isNaN("37");
Number.isNaN("37.37");
Number.isNaN("");
Number.isNaN(" ");
Polyfill
Number.isNaN = Number.isNaN || function(value) {
return typeof value === "number" && isNaN(value);
}
Especificações
Especificação | Estado | Comentário |
---|---|---|
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Number.isnan' in that specification. |
Standard | Definição inicial. |
Compatibilidade dos browsers
We're converting our compatibility data into a machine-readable JSON format.
This compatibility table still uses the old format,
because we haven't yet converted the data it contains.
Find out how you can help!
Funcionalidade | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | 25 | 15 (15) | No support | (Yes) | 9 |
Funcionalidade | Android | Chrome para Android | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | No support | ? | 15.0 (15) | No support | No support | iOS 9+ |