Creating objects with variable properties

Question

I'm trying to do this:

var sortAfter = req.query.sortAfter || '_id';
var ascending = req.query.direction || -1;
var sorted = {sortAfter: ascending};

But a console.log(sorted) output the following object:

{ sortAfter: -1 }

It's like the first variable is not used in the object creation...

Question: How do i get the object to be made of two variables, and not one variable and one fixed string?

possible duplicate of [Passing in dynamic key:value pairs to an object literal?](http://stackoverflow.com/questions/4119324/passing-in-dynamic-keyvalue-pairs-to-an-object-literal) — Felix Kling, Oct 23 '13 at 08:22

score 2 · Accepted Answer · answered Oct 23 '13 at 08:24

2

try this way:

var sortAfter = req.query.sortAfter || '_id';
var ascending = req.query.direction || -1;
var sorted = {};
sorted[sortAfter] = ascending;

answered Oct 23 '13 at 08:24

Lifecube

score 1 · Answer 2 · answered Oct 23 '13 at 08:21

1

In object literals, the keys are always literals, they're never variables. If you want to set a dynamic object key, you'll have to do it like this:

var sorted = {};
sorted[sortAfter] = ascending;

answered Oct 23 '13 at 08:21

deceze

score 1 · Answer 3 · answered Oct 23 '13 at 08:21

1

Use the subscript/bracket notation:

var sorted = {};
sorted[sortAfter] = ascending;

The subscript operator will convert its operand to a string,

answered Oct 23 '13 at 08:21

c.P.u1

3 Answers3