NULL in Javascript

A variable is a storage location that contains a value. A null represents nothing . Its not an actual value. It means that the storage location does not contain anything (but null itself is just a special kind of value).

What's the typeof null?

typeof null // "object"
The null value is technically a primitive , the way "object" or "number" are primitives. This would typically mean that the type of null should also be "null". However, this is not the case because of a peculiarity with the way JavaScript was first defined.

Why is null considered an object in JavaScript?

Actually null is not an object , it is a primitive value. For example, you cannot add properties to it. Sometimes people wrongly assume that it is an object, because typeof null returns "object". It is a JavaScript design error they can't fix now (that might even be fixed in ECMAScript 6). It should have been type null , not type object, or not have it at all. It necessitates an extra check (sometimes forgotten) when detecting real objects and is source of bugs.




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