JavaScript object declaration syntax - variable names as properties

Question

JavaScript gives you a lot of ways to declare objects. When you have most of the data available at hand, the most convenient (in my opinion) is as follows:

var person = {
    name: 'John',
    age: 23
}; // "object literal syntax"

A curious thing about this syntax is that it is identical to this:

var person = {
    'name': 'John',
    'age': 23
}; // "object literal syntax"

That is, you can use quotes or omit them for the property names.

When comparing that to the way setting a single property works, you have two options:

person.birthday = "January 12"; // "dot syntax"

or

person['birthday'] = "January 12"; // "array syntax"

The "dot syntax" only works when the right operand is the actual property name. If you want to use a variable for the property name, you have to use "array syntax", i.e.:

var prop = "birthday";
person[prop] = "January 12";

Now, is it possible to use a variable for the property name in the "object literal syntax"? Since it doesn't matter if you quote the property names, there doesn't seem to be an obvious way to use a variable there. I'm looking for something like this:

var prop = "birthday";
var person = {
    name: 'John',
    age: 23,
    (prop): 'January 12'
};

Here I'm using (prop) as the imaginary syntax used to express that this is a variable and not a literal string.

Thanks.

Answer 1

No, this will not work, that is why, if you are dynamically setting property names, array like notation is suggested and used.

var k='propertyname';
object[k]="value";

this works while using the dot notation to set index or property name from vatiable is not possible.