Local function in JavaScript object with namespace

Question

I want to create a namespace to organise all of my JavaScript. I can't see a way, using the code sample below, to create a local function so that it can't be called except from within this Object.

window.JD = window.JD || {};

JD.Guid = {

    newGuid : function() {
        return JD.Guid.s4(); // Would like this to be this.s4();
    },

    s4 : function() {
        return Math.floor((1 + Math.random()) * 0x10000);
    }
}

I have tried using JD.Guid = function() {...} but that doesn't work either. The console tells me that the function is undefined.

I'd like to be able to call JD.Guid.newGuid() from anywhere within my site.

if your local scope (because you want to call from anywhere) have JD then try calling window.JD.Guid.newGuid(), otherwise, I don't see anything wrong, you can actually call JD.Guid.newGuid() from anywhere in your site, (if no 'JD' is there in the current scope or parent hierarchy scope apart from the window's one) — Koushik Chatterjee
– Koushik Chatterjee, Commented Aug 29, 2017 at 15:26

cn0047 · Accepted Answer · 2017-08-29 15:37:23Z

1

I think you're asking about module design pattern and in this case your code must looks like:

window.JD = window.JD || {};
JD.Guid = (function () {
    // This function is private,
    // you can re-use it only from public accessible method.
    var privateMethod = function() {
        return 'private';
    };
    return {
        newGuid : function() {
            return JD.Guid.s4();
        },
        newGuidThroughtThis : function() {
            return this.s4();
        },
        privateMethod: function() {
            return privateMethod();
        },
        s4 : function() {
            return Math.floor((1 + Math.random()) * 0x10000);
        }
    }
})();

Now you can re-use your module and do something like:

console.log(JD.Guid.s4());
console.log(JD.Guid.newGuid());
console.log(JD.Guid.newGuidThroughtThis());

as output you'll get something like: 118723

edited Aug 29, 2017 at 15:37

answered Aug 29, 2017 at 15:29

cn0047

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2 Comments

ltoodee Over a year ago

Thanks, this is exactly what I'm looking for and found this link which may help others in the future toddmotto.com/mastering-the-module-pattern

cn0047 Over a year ago

Cool! Yes, link is helpful.

Mike Cheel · Accepted Answer · 2017-08-29 15:27:11Z

0

I usually do something like this:

var JD = (function(GLOBAL_JD){
      if(GLOBAL_JD === undefined) {
        var jd = {
          GUID: {
            newGuid: newGuid          
          }
        };

        return jd;
      }

  function newGuid() {
    return s4(); // Would like this to be this.s4();
  }

  function s4() {
    return Math.floor((1 + Math.random()) * 0x10000);
  }
})(JD);

console.log(JD.GUID.newGuid());

http://jsbin.com/jodifeb/edit?js,console,output

answered Aug 29, 2017 at 15:27

Mike Cheel

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Comments

Danil Speransky · Accepted Answer · 2017-08-29 15:30:12Z

0

I'm not sure that I'm following. But you can create a local function which is not accessible in global namespace by creating a context wrapping your code in a function:

(function() {
  window.JD = window.JD || {};

  function s4() {
    return Math.floor((1 + Math.random()) * 0x10000);
  }

  JD.Guid = {
    newGuid: function() {
      return s4();
    }
  }
})();

edited Aug 29, 2017 at 15:30

answered Aug 29, 2017 at 15:19

Danil Speransky

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1 Comment

ltoodee Over a year ago

Yes it does although another answer talks about the module design pattern, which is exactly the sort of thing I'm after. Your answer does match the question though.

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