Hacker News new | ask | show | jobs
by BillyTheKing 1703 days ago
exactly.. the 'only' billion dollar mistake in JS in regards to null is that typeof null === 'object' => true
1 comments
colejohnson66 1703 days ago
It’s not undefined, therefore it’s an object. And because every type can be null, it makes sense that it’s just “object”, not “string” or whatever.
link
goto11 1703 days ago
It it just a mistake or oversight in the definition of the language. It doesn't really make logical sense that a null is an object but a string is not an object.

It would kind of make sense in Java, where only object types can be null. But that distinction does not exist in JavaScript.

link
afiori 1703 days ago
typeof null should be "null", just how typeof undefined is "undefined"

it is an implementation bug of netscape, null was represented by the zero pointer and objects where tagged pointer with a tag of zero, so when reading its tag null looked like an object.

there are solutions as x == null, x === null, and Object(x) == x allow you to check for null|undefined, null, and object values, but typeof null being "object" is purely a specification bug that it is too late to change.

link