How to add an object containing arrays to a class

Question

I'm looking to implement something like this:

var settings = (function () {
    this.data = {
        array1: [],
        array2: [],
        array3: []
    };

    this.hasSettings = function () {
            //todo
    };
})();

What I'd like to do with it is:

settings.data.array1.push(item);

Unfortunately i get an:

Uncaught TypeError: Cannot set property 'datas' of undefined

Could someone help me and explain the corrrect way to implement this?

Regards

this === the outer context. To use the function as a constructor you need to call it with new myFun(),. Instead you are calling it right away. — spelufo
– spelufo, Commented Feb 2, 2015 at 13:12

Kirill Pisarev · Accepted Answer · 2015-02-02 13:39:45Z

1

white console.log(this) inside your IIFE... this is a window object. To make your code work change IIFE to immediately creating instance:

var settings = new function () {
    this.data = {
        array1: [],
        array2: [],
        array3: []
    };

    this.hasSettings = function () {
            //todo
    };
};

When you write new function(){...}, you immediately call a constructor function with new keyword. The new keyword creates a new object with properties of this and returns it (unless the constructor function returns a non-primitive value).

When you used IIFE, you just populated global object (window in browsers) with properties of this.

edited Feb 2, 2015 at 13:39

answered Feb 2, 2015 at 13:13

Kirill Pisarev

8434 silver badges11 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

How to add an object containing arrays to a class

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related