How to provide namespaces in JavaScript with instanced objects

Question

I've got a JavaScript "object", built this way:

function foo()
{
    this.length = 0;
}

foo.prototype.getLength = function()
{
    return this.length;
}

...

I know how to emulate namespaces with singleton JavaScript objects, but what is the best way to "namepace" an object such as that above that will intanced?

I know that several JavaScript libraries have namepacing capabilities, but I'm using jQuery and would rather not add another library to the mix. I'd like to be able to provide my own, perhaps by exploiting jQuery, intrinsic namespacing scheme for the JS objects of mine that need to be instanced.

Jason Bunting · Accepted Answer · 2008-08-22 18:18:30Z

12

Simple:

if(!MyNamespace) MyNamespace = {};

MyNamespace.foo = function() {
   this.length = 0;
};
MyNamespace.foo.prototype.getLength = function() {
   return this.length;
};

answered Aug 22, 2008 at 18:18

Jason Bunting

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1 Comment

Jason Bunting Over a year ago

@Chameleon - huh? What are you talking about?! "prototype" is a property automatically, it doesn't have to be "created" per se

bvrakvs · Accepted Answer · 2017-04-21 10:19:05Z

8

Javascript doesn't really have namespace or packages like other languages. Instead it has closures. If you have an application that consists of multiple functions, variables and objects, then you should put them inside a single global object. This will have the same effect as a namespace.

For example:

var namespace = {
  this.foo: function(){
    ...
  },
  this.foo.prototype.getLength: function(){
    ...
  }
}

You could also create a set of nested objects and simulate packages:

loadPackage = function(){
  var path = arguments[0];
  for(var i=1; i<arguments.length; i++){
    if(!path[arguments[i]]){
      path[arguments[i]] = {};
    }
    path = path[arguments[i]];
  }
  return path;
}

loadPackage(this, "com", "google", "mail") = {
  username: "gundersen",
  login: function(password){
    ...
  }
}
this.com.google.mail.login("mySecretPassword");

edited Apr 21, 2017 at 10:19

bvrakvs

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answered Aug 22, 2008 at 19:03

Marius

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1 Comment

harpo Over a year ago

Good tips -- but I think you want colons instead of semicolons in your first example, no?

Nickolay · Accepted Answer · 2008-08-22 17:41:59Z

2

Shouldn't be much different:

namespace.foo = function foo() {...}
namespace.foo.prototype.getLength = function() { ... }

or you could use

(function() {
  function foo() { ... }
  foo.prototype...
  namespace.foo = foo;
})();

to save some typing.

answered Aug 22, 2008 at 17:41

Nickolay

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Comments

bvrakvs · Accepted Answer · 2017-04-21 10:19:40Z

2

Both answers were very helpful! Here's what I ended up with:

if( typeof( rpNameSpace ) == "undefined" ) rpNameSpace = {};

rpNameSpace.foo = function() {
    this.length = 613;
}
rpNameSpace.foo.prototype.getLength = function() {
    return this.length * 2;
}

Then, to use the resulting "namespaced" object:

var x = new rpNameSpace.foo()

display( x.getLength() );

edited Apr 21, 2017 at 10:19

bvrakvs

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answered Aug 22, 2008 at 20:56

rp.

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Comments

Tengiz · Accepted Answer · 2013-05-13 15:26:50Z

-1

Another alternative may be the bob.js framework:

bob.ns.setNs('myApp.myFunctions', { 
    say: function(msg) {  
        console.log(msg); 
    } 
}); 

//sub-namespace
bob.ns.setNs('myApp.myFunctions.mySubFunctions', { 
    hello: function(name) { 
        myApp.myFunctions.say('Hello, ' + name); 
    } 
}); 

//call:
myApp.myFunctions.mySubFunctions.hello('Bob');

edited May 13, 2013 at 15:26

answered Apr 4, 2013 at 20:04

Tengiz

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