javascript fails when populating array

Question

When I run the following javascript, it fails when input_array[input_array.length] = id; is not commented out. Can anyone see what is causing this?

function cat_images_low_lag () {
    var input_array = new array ();

    cat_images = $(".category-description").next().find("img");
    cat_images.each(function () { 
        url = $(this).parent().attr("href");
        id = url.split("id=");
        id = id[1];

        input_array[input_array.length] = id;
    });
    alert ("trst");
    alert(input_array.join("\n"));
}

cheers!

It should be Array, capital "A", or better yet just var input_array = []; — Pointy
– Pointy, Commented Nov 2, 2012 at 16:44

Praveen Kumar Purushothaman · Accepted Answer · 2012-11-02 16:44:37Z

3

First thing, replace:

var input_array = new array ();

With:

var input_array = new Array();

And use this to insert:

input_array.push(id);

Or directly add:

input_array[input_array.length] = id;

Other ways to initialize arrays:

var input_array = [];

answered Nov 2, 2012 at 16:44

Praveen Kumar Purushothaman

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3 Comments

HBP Over a year ago

or even var input_array = []

Praveen Kumar Purushothaman Over a year ago

@HBP Yes, you can... :) Added it too! :)

tracer tong Over a year ago

forgot javascript is case sensitive!

I Hate Lazy · Accepted Answer · 2012-11-02 17:01:37Z

1

Others noted the capitalization problem, but since you're using jQuery, a nicer way to build the Array is like this:

function cat_images_low_lag () {
    var input_array = $(".category-description + * img").map(function () { 
        return this.parentNode.href.split("id=")[1];
    }).toArray();

    alert ("trst");
    alert(input_array.join("\n"));
}

answered Nov 2, 2012 at 17:01

I Hate Lazy

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3 Comments

Shmiddty Over a year ago

I'm not sure that your query selector is correct. I believe next selects only the next sibling, while + * would select all elements that follow .category-description.

I Hate Lazy Over a year ago

@Shmiddty: You're thinking of the ~ selector. :) The + selects only the next element sibling.

Shmiddty Over a year ago

You're right. I tend to use the + selector in the context of li, so it ends up styling all elements but the first li, but only because each is immediately preceded by an li.

Travis J · Accepted Answer · 2012-11-02 16:50:53Z

0

Your initialization of the array is incorrect

var input_array = new array ();

You should use the shorthand

var input_array = [];

or

var input_array = new Array();

Moreover, to avoid having cat_images be a variable in the global scope, you may want to consider scoping it locally like this

var cat_images = $(".category-description").next().find("img");

edited Nov 2, 2012 at 16:50

answered Nov 2, 2012 at 16:45

Travis J

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1 Comment

Pointy Over a year ago

It's OK in JavaScript for the index to be greater than the array length. The language explicitly supports that.

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