In javascript, what is the difference between an object and a namespace?

Question

While reading "Object-Oriented JavaScript" on Mozilla's website, I stumbled upon this note:

It's important to note that in JavaScript there's no language-level difference between regular objects and namespaces.

However, the note is not clear about what is meant by "language-level difference".

Does it mean there are two ways of writing the same thing? Or that there are two terms that refer to the same thing?

Answer 1

You've taken the quote out of context. The answer is in the paragraph above the quote:

A namespace is a container which allows developers to bundle up functionality under a unique, application-specific name. In JavaScript a namespace is just another object containing methods, properties, and objects.

^{(Emphasis mine)}

The quote:

It's important to note that in JavaScript there's no language-level difference between regular objects and namespaces.

Is just saying that this means a "namespace" is just a object used as a "namespace".
There are no "real" namespaces in JS.

Answer 2

Some languages have an actual namespace which is not the same thing as an object. JavaScript is not one of those languages, so objects are used for this purpose.

For example, the Math functions like Math.round and Math.abs, are all namespaced in the Math object. They aren't really contextual methods like toString is (at least not in any implementation I've found), just collected under an object to keep it organized. *

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* They are technically methods, because they are accessible by a property on an object (a definition that technically makes all global functions methods because they are available through the global object (ie. window.Function())), but unlike methods like toString, or the methods of most console implementations like console.log they do not depend on the object they are called on and the this value is irrelevant. The Math object is used purely for namespacing, not because of the context it gives.