Are object properties assigned in the same order they are declared?

Question

I have a JavaScript function that needs to return different objects depending on some variables.

return {
  source: fSource,
  a: readArray(),
  b: readArray()
};

Is there any guarantee that the interpreter assigns the first return value of readArray to a and the second to b? I could easily rewrite it to:

var tmp = {
  source: fSource,
};
tmp.a = readArray();
tmp.b = readArray();
return tmp;

But I have a lot of such code and the first notation is quite pretty.

I know that the order of object properties might change but I doubt this affects my case.

Update:

To clarify my concerns:

var a = {
  foo: fn1(),
  bar: fn2()
};

I don't care about the order of foo and bar in the object. But is it possible that fn2 is called before fn1?

This affects any cases in JavaScript objects. Initially object properties are not ordered and browsers may treat it differently. If you care of the order you'd better use array. — VisioN, Oct 11 '13 at 14:32
@VisioN I don't care about the order of properties, I care about the order of invocations. — just lerning, Oct 11 '13 at 14:34
Ah, that makes more sense. The order of invocations should be the same. — VisioN, Oct 11 '13 at 14:35
Potential duplicates: http://stackoverflow.com/questions/17437965/javascript-object-initialization-and-evaluation-order and http://stackoverflow.com/questions/16200387/are-javascript-object-properties-assigned-in-order — hopper, Oct 11 '13 at 14:50

score 1 · Accepted Answer · answered Oct 11 '13 at 14:38

1

_{Answering on your update...}

No, it is not possible.

The function invocations will go in the same order as you have declared in the code.

answered Oct 11 '13 at 14:38

VisioN