Why do we use "var" in object literal notation if object literals are not variables?

Question

This is what object literal syntax looks like:

var x = {property:value};

Now, please correct me if I am wrong but what I'm looking at is the word "var" here, and that seems to imply "variable". Does this mean that fundamentally "objects" are variables (with the caveat that they behave similar to arrays)? I recently asked a question about whether variables were objects and everyone said no.

But it's strange that the keyword "var" is used when creating an object literal, and if they aren't variables (which I'm assuming for now) why would ecmascript incorporate this use if object literals are not in some way or another variables? It seems syntactically confusing.

An object is an object, which is a value. A variable is a location, and you're assigning the value to it. You can use object literals without variables as well - they're basic expressions, and can be used e.g. as a function argument. — Bergi
– Bergi, Commented Jun 10, 2014 at 22:24

Ry- · Accepted Answer · 2014-06-10 22:22:35Z

2

The object { property: value } is not a variable, but x is, and that’s what the var refers to. var creates a variable, and optionally gives it a value; x is the variable, and { property: value } is the object you’re assigning to it. The object has nothing to do with a variable. Consider

var x = 5;

5 isn’t a variable.

var x = null;

null isn’t a variable.

console.log({ foo: 70 }.foo + " boxes");

No variables involved here, but there is an object literal, just like 70 is a numeric literal and " boxes" is a string literal.

answered Jun 10, 2014 at 22:22

Ry-♦

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2 Comments

Allan Socks Over a year ago

Thank you very much, I think I get it now. (I pressed return too soon btw, and it send my message, I wasn't ready to respond yet)

user3117575 Over a year ago

@AllanSocks, if you created and array, the array wouldn't be the variable, it would be whatever you're assigning the array to. var x = ["test", "test2", "test3"]... The array would just be the variables value.

Niet the Dark Absol · Accepted Answer · 2014-06-10 22:23:04Z

0

The variable here is x. You are declaring x and then assigning it to point to an object literal.

Remember that with hoisting, your code ends up being processed like this:

var x;
x = {property:value};

As you can see, it really doesn't matter what you set x to, or even if you don't set it at all. var x declares a variable in the current scope named x.

answered Jun 10, 2014 at 22:23

Niet the Dark Absol

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