Javascript - Array of 'classes'

Question

I'm trying to create an array of 'classes' like so:

function Main(initURL){

    var item_array = [];

    this.initURL = initURL;

    function construct() {
        $.ajax({ 
            url: initURL,
            dataType: 'json',
            success: function(data){
                for(var i=0;i<data.length;i++){
                    var item = new Item(data[i]);
                    item_array.push(item);
                }
                init();
            }
        });
    }

    function init() {
        setInterval(update, 1000);
    }

    function update() {
        for(var item in item_array){
            console.log(item.name);
        }
    }

    construct();
}

function Item(data) {

    var dirty = false;

    function init(data) {
        this.id = data.pk;
        this.name = data.fields.name;
    }

    init(data);
}

When attempting to print out the item name, I'm getting "undefined". Is there more to it than this? Data.field.name is definitely set.

Ry- · Accepted Answer · 2011-05-24 18:02:45Z

3

A for..in loop loops through keys, not values. Change it to:

for(var i = 0; i < item_array.length; i++) {
    console.log(item_array[i].name);
}

edited May 24, 2011 at 18:02

answered May 23, 2011 at 16:51

Ry-♦

226k56 gold badges496 silver badges504 bronze badges

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

Comments

Matt Ball · Accepted Answer · 2011-05-23 16:51:21Z

3

Don't use for... in to iterate over an array.

for(var i=0; i < item_array.length; i++){
    console.log(item_array[i].name);
}

https://developer.mozilla.org/en/JavaScript/Reference/Statements/for...in#Description

answered May 23, 2011 at 16:51

Matt Ball

361k102 gold badges655 silver badges725 bronze badges

Comments

Pointy · Accepted Answer · 2011-05-23 16:52:19Z

0

The problem is that you're calling your "init()" function in "Item()" without any context object. Thus, this isn't the object you want it to be. Try this change:

function Item(data) {
  var item = this;
  function init(data) {
    item.id = data.pk;
    item.name = data.fields.name;
  }
  init(data);
}

Now, I'm not sure why you'd want to write the function that way in the first place; that little "init()" function doesn't really do anything useful. It could just be:

function Item(data) {
  this.id = data.pk;
  this.name = data.fields.name;
}

and that would work too.

answered May 23, 2011 at 16:52

Pointy

415k62 gold badges600 silver badges631 bronze badges

Collectives™ on Stack Overflow

Javascript - Array of 'classes'

3 Answers 3

Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related