Feb 22, 2011 · From the preceding examples, it is clear that undefined and null are two distinct types: undefined is a type itself (undefined) while null is an object. Proof :

Oct 2, 2012 · It can be helpful to have predictable types and this can guide thinking to use one or another. Where an object is always returned, needed or wanted by design, use null for falsy results …

Aug 31, 2012 · According to What is the difference between null and undefined in JavaScript?, null and undefined are two different objects (having different types) in Javascript. But when I try this code var …

Feb 24, 2011 · How do I check a variable if it's null or undefined and what is the difference between the null and undefined? What is the difference between == and === (it's hard to search Google for "===" )?

Diferença semântica Como já apontado nas respostas do Calebe Oliveira e do Alexandre Marcondes, existe uma diferença semântica entre null e undefined: o valor null é utilizado para indicar a …

Quite a few of them are to do with null and undefined (did you know it's actually possible to redefine the value of the built-in undefined object?!), and most of them come with an explanation as to what's …

I can't find any difference between typeof somevar == 'undefined' and typeof somevar === 'undefined', because typeof always returns string. For null it will return 'object'.

While literally using the keyword undefined, Boolean(undefined) works, trying that with an undefined variable doesn't work, and that is the whole point of doing the check for null or undefined.

Jan 7, 2025 · Cuál es la diferencia en JavaScript entre una variable undefined y una variable null? cómo puedo saber si una variable está null, undefined o ambos? también quisiera saber si son lo mismo?

However, because of the advantage that null cannot be redefined, I might would use it when using ==. For example, variable != null will ALWAYS return false if variable is equal to either null or undefined, …