Javascript - Array of 'classes'

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',
            suc开发者_如何学编程cess: 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.

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);
}

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

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.