Share prototype instance through requirejs without singelton pattern?

Question

I got a mediator object which handles sandboxes.

Each sandbox has to register at the mediator. Because I also use requirejs this is a little problem because I have no idea how I could share the instance and not the prototype:

mediator.js

define([], function() {
    var Mediator = function() {};
    Mediator.prototype.start = function() {};
    Mediator.prototype.stop = function() {};
    Mediator.prototype.register = function() {};
    Mediator.prototype.unregister = function() {};
    return Mediator;
});

sandbox_one.js

define(['mediator'], function(Mediator) {
    var mediator = new Mediator();
    mediator.register('sandboxOne', SandboxObject);
});

sandbox_two.js

define(['mediator'], function(Mediator) {
    var mediator = new Mediator();
    mediator.register('sandboxtwo', SandboxObject);
});

As you have mentioned with the current approach I register the sandboxes at two different mediators. One idea to solve this would be the use of a singleton pattern but this conflicts with the architecture and requirejs recommandations..

So what other ways would I have to let the sandboxes register all to the same instance of Mediator?

Can you explain a bit more? If you use the same instance everywhere, then you will have a singleton anyway, no matter how you call it? — JohnB, Sep 23 '12 at 08:50

score 2 · Accepted Answer · edited May 23 '17 at 12:12

2

Since I can't post comments, I'm going to post an answer.

ggozad explains how to do a singleton in RequireJS here: Is it a bad practice to use the requireJS module as a singleton?

His code:

define(function (require) {
    var singleton = function () {
        return {
            ...
        };
    };
    return singleton();
});

edited May 23 '17 at 12:12

Community

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answered Sep 23 '12 at 09:22

Jan Sommer

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There is no reason to have that `singleton` function - just return the object literal – Bergi Sep 23 '12 at 09:38
@ZenMaster: You already do have that with the anonymous function for `define`… – Bergi Sep 23 '12 at 19:21
@Bergi Nope. I meant for scope inside the anonymous function. Default values (starting values) for singleton. – ZenMaster Sep 23 '12 at 19:31

score 0 · Answer 2 · answered Feb 26 '14 at 13:25

Actually, with RequireJS you are already receiving singletons, so if you call:

require(['mediator'], function(Mediator) {
  ....
});

Mediator will be always the same object. If it's a constructor function, by calling new Mediator() you'll always create a new instance, but you'll use the same function each time.

But you don't have to return a function:

define([], function() {
    return {
        start: function() {},
        stop: function() {},
        register: function() {},
        unregister: function() {}
    };
});

Now your Mediator will be an instance, not a function, and you can't use it as function. You're example would now look like:

require(['mediator'], function(Mediator) {
  Mediator.register('sandboxOne', SandboxObject);
});

Disclaimer: I'm using RequireJS version build-in in Dojo.

Share prototype instance through requirejs without singelton pattern?

2 Answers2