I want to create a global namespace for my application and in that namespace I want other namespaces:
E.g.
Dashboard.Ajax.Post()
Dashboard.RetrieveContent.RefreshSalespersonPerformanceContent();
I also want to place them in seperate files:
However I have tried using this method, however it won't work because the same variable name is being used for the namespace in 2 seperate places. Can anyone offer an alternative?
Thanks.
You could do something like this...
HTML page using namespaced library:
<html>
<head>
<title>javascript namespacing</title>
<script src="dashboard.js" type="text/javascript"></script>
<script src="ajax.js" type="text/javascript"></script>
<script src="retrieve_content.js" type="text/javascript"></script>
<script type="text/javascript">
alert(Dashboard.Ajax.Post());
alert(Dashboard.RetrieveContent.RefreshSalespersonPerformanceContent());
Dashboard.RetrieveContent.Settings.Timeout = 1500;
alert(Dashboard.RetrieveContent.Settings.Timeout);
</script>
</head>
<body>
whatever...
</body>
</html>
Dashboard.js:
(function(window, undefined){
var dashboard = {};
window.Dashboard = dashboard;
})(window);
Ajax.js:
(function(){
var ajax = {};
ajax.Post = function() { return "Posted!" };
window.Dashboard.Ajax = ajax
})();
Retrieve_Content.js:
(function(){
var retrieveContent = {};
retrieveContent.RefreshSalespersonPerformanceContent = function() {
return "content retrieved"
};
var _contentType;
var _timeout;
retrieveContent.Settings = {
"ContentType": function(contentType) { _contentType = contentType; },
"ContentType": function() { return _contentType; },
"Timeout": function(timeout) { _timeout = timeout; },
"Timeout": function() { return _timeout; }
};
window.Dashboard.RetrieveContent = retrieveContent;
})();
The Dashboard.js acts as the starting point for all namespaces under it. The rest are defined in their respective files. In the Retrieve_Content.js, I added some extra properties in there under Settings to give an idea of how to do that, if needed.
The Yahoo Namespace function is exactly designed for this problem.
Added:
The source of the function is available. You can copy it into your own code if you want, change the root from YAHOO to something else, etc.
You just need to make sure that you don't stomp on your namespace object if it's already been created. Something like this would work:
(function() {
// private vars can go in here
Dashboard = Dashboard || {};
Dashboard.Ajax = {
Post: function() {
...
}
};
})();
And the RetrieveContent file would be defined similarly.
There are several libraries that already offer this sort of functionality if you want to use or examine a pre-baked (that is, a tested) solution.
The simplest and most bug free one to get going with is probably jQuery.extend, with the deep argument set to true. (The reason I say it is bug free is not because I think that jQuery.extend suffers from less bugs than any of the other libraries -- but because it offers a clear option to deep copy attributes from the sender to the receiver -- which most of the other libraries explicitly do not provide. This will prevent many hard-to-diagnose bugs from cropping up in your program later because you used a shallow-copy extend and now have functions executing in contexts you weren't expecting them to be executing in. (If however you are cognizant of how you will be extending your base library while designing your methods, this should not be a problem.)
I believe the module pattern might be right up your alley. Here's a good article regarding different module patterns.
http://www.adequatelygood.com/2010/3/JavaScript-Module-Pattern-In-Depth
With the NS object created, you should just be able to add to it from where ever. Although you may want to try var NS = NS || {}; to ensure the NS object exists and isn't overwritten.
// NS is a global variable for a namespace for the app's code
var NS = NS || {};
NS.Obj = (function() {
// Private vars and methods always available to returned object via closure
var foo; // ...
// Methods in here are public
return {
method: function() {
}
};
}());