Passing variables between two JavaScript modules not working

Question

I have two modules within the same namespace, and I want to pass a variable between them. The namespace is called app, and the variable is a - but for some reason my variable a always comes out null when my method is called.

Here is the code:

// module 1
(function() {
    app.module1 = (function() {
        var a = null; 
        canvas.addEventListener('mousedown', function(e) {
            a = { message: hallo };
            app.module2.print();
        }, 0);

        return {
            a: a
        };
    })();
})();

// module 2

(function() {
    app.module2 = (function() {
        var print = function() {
            console.log(app.module1.a);
        }

        return {
            print: print
        };
    })();
})();

Did you mean to have a = { message: "hallo" };? Where hallo becomes a string? Or is that defined somewhere off the screen? — Ian
– Ian, Commented May 3, 2013 at 23:49

sites · Accepted Answer · 2013-05-03 23:19:15Z

1

Check this jsbin

Basically what you can do is to calculate variable each time:

In your module 1:

a: function(){return a;}

Wherever you are using a:

console.log(app.module1.a());

answered May 3, 2013 at 23:19

sites

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1 Comment

user1477955 Over a year ago

console prints ERROR: a is not a function

Joseph · Accepted Answer · 2013-05-04 01:10:22Z

1

It's because your handler is referring to the local a and not the a property on the module. I suggest you modify the object instead, or you could do this:

// module 1
(function () {
  app.module1 = (function () {
    var interface = {
      a: null
    };
    canvas.addEventListener('mousedown', function (e) {
      //this way, you are modifying the object
      interface.a = {
        message: hallo
      };
      app.module2.print();
    }, 0);
    return interface;
  })();
})();

edited May 4, 2013 at 1:10

answered May 3, 2013 at 23:02

Joseph

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