Javascript - Function Declaration within Object

Question

I am attempting to use a function declaration within an object but am so far unable to. I know I can use function expressions within an object but is it possible to use function declarations instead?

This works:

 var objContainer = {};
 objContainer.callback = function(data) {
 objContainer.server_date = data.responseXML.documentElement.getAttribute("answer");
 alert("Object should have XML response: " + objContainer.server_date);
 };

This doesn't:

 var objContainer = {};
 function objContainer.callback(data) {
 objContainer.server_date = data.responseXML.documentElement.getAttribute("answer");
 alert("Object should have XML response: " + objContainer.server_date);
 }

I also tried using a function declaration using object literal notation but it also fails:

 var objContainer = {
   function callback(data) {
   var objContainer.server_date = data.responseXML.documentElement.getAttribute("answer");
   alert("Object should have XML response: " + objContainer.server_date);
   }
 };

You could use a factory but that wouldn't be so different from the first code. what's your problem with it ? — Denys Séguret
– Denys Séguret, Commented Mar 27, 2013 at 17:32
I don't understand what benefit the declaration has that the expression doesn't. — Kendall Frey
– Kendall Frey, Commented Mar 27, 2013 at 17:35

Quentin · Accepted Answer · 2013-03-27 17:32:52Z

2

I know I can use function expressions within an object but is it possible to use function declarations instead?

No. Only expressions.

The closest you could get would be to have a function declaration in scope, and then assign the function to an object property by name.

function foo () { }
var bar = { func: foo };

answered Mar 27, 2013 at 17:32

Quentin

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Comments

Gavin · Accepted Answer · 2013-03-27 17:49:16Z

1

If I'm understanding you correctly, you just want to use the "function funcname() { .. }" syntax instead of "obj.prop = function() { .. }" correct? The only way you'll be able to do that is using something like this:

function objContainer() {
    this.callback = callback;
    function callback(data) {
        alert(data);
    }
};

var myObjectContainer = new objContainer();
myObjectContainer.callback('hello world');

When you call a function using "varName = new funcName()" it creates an object.

answered Mar 27, 2013 at 17:49

Gavin

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Comments

IJMorgado · Accepted Answer · 2013-03-27 17:38:09Z

0

For the last one example I think this is what you want:

var objContainer = {
  callback : function(data) {
 var objContainer.server_date = data.responseXML.documentElement.getAttribute("answer");
  alert("Object should have XML response: " + objContainer.server_date);
                         }
                  };
//  then you could use the object like this:
objContainer.callback();

answered Mar 27, 2013 at 17:38

IJMorgado

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