How can I create a JavaScript object constructor in a module?

Question

I am trying to create a reusable javascript object (I want to use new). When I attempt to new up one of my custom objects I get an error:

"org.myorg.sadp.section.sadpSection is not a constructor"

I am modularizing my JS for namespace reasons. I wonder if that is the problem:

if (!window.org) var org = { myorg: {} };    
if (!org.myorg) org["myorg"] = { sadp: {} };
if (!org.myorg.sadp) org.myorg["sadp"] = {};

org.myorg.sadp.section = (function(ns) {
    if (ns.section) {
        return ns;
    }
    else {
        ns.section = {};
    }
    ns.section.sadpSection = function(name) {
        this.name = name;
        this.isCompleted = false;
        this.booleanQuestions = new Array();
        this.multipleChoiceQuestions = new Array();
        this.sliders = new Array();
        return true;
    }
    return ns;

} (org.myorg.sadp))

This results in the error:

var myObj = new  org.myorg.sadp.section.sadpSection("test");

What am I doing wrong here?

Thanks!

Matthew Flaschen · Accepted Answer · 2011-03-06 06:56:29Z

2

You're basically making org.myorg.sadp.section equal org.myorg.sadp. This isn't want you want, and it's basically infinite recursion:

org.myorg.sadp.section == org.myorg.sadp.section.section

and the same is true no matter how many .sections you add. You can change it to:

org.myorg.sadp.section = 
{
    sadpSection: function(name)
    {
        this.name = name;
        this.isCompleted = false;
        this.booleanQuestions = new Array();
        this.multipleChoiceQuestions = new Array();
        this.sliders = new Array();
    }
}

You can add a:

if(!org.myorg.sadp.section.sadpSection)

to avoid reassigning the constructor.

That isn't any less modular. The return true is also unnecessary.

edited Mar 6, 2011 at 6:56

answered Mar 6, 2011 at 6:45

Matthew Flaschen

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1 Comment

Aleksi Yrttiaho Over a year ago

That is to say remove .section from the line org.myorg.sadp.section = (function(ns) and you're set.

Gabriel · Accepted Answer · 2011-03-06 06:53:22Z

0

I recently wrote a namespace library for handling this type of module system you may want to check out. The idea is that you would use it like this:

ns('org.myorg.sadp.section');

org.myorg.sadp.section.load('sadpSection', function(name) {
    this.name = name;
    this.isCompleted = false;
    // always better to use array literals than constructor
    this.booleanQuestions = []; 
    this.multipleChoiceQuestions = [];
    this.sliders = [];
    return true;
});

but basically the problem you are dealing with is that you are returning ns instead of section.

answered Mar 6, 2011 at 6:53

Gabriel

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Comments

Xyz · Accepted Answer · 2020-09-25 08:17:06Z

0

Your problem is this bit here:

org.myorg.sadp.section = (function(ns) {

It should be:

org.myorg.sadp = (function(ns) {

edited Sep 25, 2020 at 8:17

Xyz

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answered Mar 6, 2011 at 6:59

Mike M. Lin

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