olliej olliej - 11 days ago 6
Javascript Question

Is there a "concise" way to do namespacing in JavaScript?

I've frequently encountered sites that put all of their javascript inside a "namespace" structure along the lines of

namespaces = { com : { example: { example.com's data} }


But setting this up safely with respect to other namespaced frameworks seems to require a relatively hefty amount of code (defined as > 2 lines). I was wondering whether anyone knows of a concise way to do this? and whether there's a relatively standard/consistent way to structure it? eg. is the "com" namespace directly attached to the global object, or is it attached through a namespace object?

[Edit: whoops, obviously
{com = { ... } }
wouldn't accomplish anything close to what i intended, thanks to Shog9 for pointing that out. :D]

Answer

Javascript doesn't have stand-alone namespaces. It has functions, which can provide scope for resolving names, and objects, which can contribute to the named data accessible in a given scope.

Here's your example, corrected:

var namespaces = { com: { example: { /* example.com's data */ } } }

This is a variable namespaces being assigned an object literal. The object contains one property: com, an object with one property: example, an object which presumably would contain something interesting.

So, you can type something like namespaces.com.example.somePropertyOrFunctionOnExample and it'll all work. Of course, it's also ridiculous. You don't have a hierarchical namespace, you have an object containing an object containing an object with the stuff you actually care about.

var com_example_data = { /* example.com's data */ };

That works just as well, without the pointless hierarchy.

Now, if you actually want to build a hierarchy, you can try something like this:

com_example = com_example || {};
com_example.flags = com_example.flags || { active: false, restricted: true};

com_example.ops = com_example.ops || (function()
    {
       var launchCodes = "38925491753824"; // hidden / private
       return {
         activate: function() { /* ... */ },
         destroyTheWorld: function() { /* ... */ }
       };
    })();

...which is, IMHO, reasonably concise.