Unable to return length of array created in javascript

Question

I created an array which contains query string values from url

var vars = [], hash;
var hashes = window.location.href.slice(window.location.href.indexOf('?') + 1).split('&');

for (var i = 0; i < hashes.length; i++) {
     hash = hashes[i].split('=');
     vars[hash[0]] = hash[1];
}

If I want to iterate it, won't happens anything:

$.each(query_array, function(k, v) {
   console.log(v);
});

Then I wrote

console.log(query_array.length);

But my array looks like in Chrome console:

[keyword: "mercedes", redirectTo: "test.aspx", remove: function]

The length returns 0. Why ?

How could I iterate through this kind of array ?

I ran your function, and I think the arrays are actually different of what you wrote. — Artyom Neustroev
– Artyom Neustroev, Commented Jun 28, 2013 at 6:00

Artyom Neustroev · Accepted Answer · 2013-06-28 06:04:07Z

3

If you make vars an object, not an array it will work fine for you:

var vars = {}, hash;
var hashes = window.location.href.slice(window.location.href.indexOf('?') + 1).split('&');

for (var i = 0; i < hashes.length; i++) {
     hash = hashes[i].split('=');
     vars[hash[0]] = hash[1];
}

console.log(vars) //Object {keyword: "mercedes", redirectTo: "test.aspx", remove: function}

You cannot access an array's element by an index, that is not a number. In your case - the index is not a number.

answered Jun 28, 2013 at 6:04

Artyom Neustroev

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Comments

M.G.Manikandan · Accepted Answer · 2013-06-28 06:04:07Z

2

var vars = [] should be changed to var vars = {} as your creating Object. [] represents Array.

Then, $.each will work.

Also you can get query string using location.search instead of location.href. Please check the updated code below

var vars = {}, hash;
var hashes = window.location.search.substring(1).split('&');

for (var i = 0; i < hashes.length; i++) {
     hash = hashes[i].split('=');
     vars[hash[0]] = hash[1];
}

answered Jun 28, 2013 at 6:04

M.G.Manikandan

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Comments

Darin Dimitrov · Accepted Answer · 2013-06-28 06:05:19Z

1

vars is not an array. In javascript arrays must always have integer indexes. In your case you using strings as indexes:

vars[hash[0]] = hash[1];

So don't create an array, just create an object:

var vars = {}, hash;

and you will be able to iterate over the properties of this object:

$.each(vars, function(k, v) {
    console.log(k + ': ' + v);
});

answered Jun 28, 2013 at 6:05

Darin Dimitrov

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Comments

mohkhan · Accepted Answer · 2013-06-28 06:09:23Z

1

Ok, I'll give a detailed explanation for this.

Every object in JavaScript can act like a Map(Dictionary). Something like this.

var a = new Object();
a["foo"] = 10;
a["bar"] = 20;

...

Even an Array ([]) is an object. So it will respect the same behavior. Like this...

var arr = [];
arr["foo"] = 10;
arr["bar"] = 20;

But this does not mean you are using the Array as it is supposed to be used. Even though you have added properties to your Array, you have NOT added any element to the array and because of that the length count is 0. So maybe you should keep the count as a separate key/value pair.

Hope you understood.

answered Jun 28, 2013 at 6:09

mohkhan

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