Access Javascript array dynamically

Question

This code is reading the first letter of the arrays name, but I want it to read the first object in that array. It's supposed to read an elements array attribute (which it does) then access the first thing in that array. This is my first time working with arrays so this may be a very silly question :)

Thanks heaps.

//array of strategies
//leads
var leads = new Array();
leads[0] = "Test 1";
leads[1] = "Test 2";
leads[2] = "Test 3";

$("button").click(function () {
    //get category
    var currentCat = $(this).attr("array");
    $("#danWell h1").text($(this).attr('id')); //don't worry about this line
    $("#danWellContent").text(currentCat[0]);
})

Do you have a working Plunk or JSFiddle? It's hard to say what your issue is without more code. — Tyler Eich
– Tyler Eich, Commented Nov 24, 2013 at 21:20
$(this).attr("array"); ??? Put a full code example directly in your question. How does leads work into your situation? — Blue Skies
– Blue Skies, Commented Nov 24, 2013 at 21:21
currentCat is going to be the value of an attribute, which can only be a string. Where does the array come into it? — Quentin
– Quentin, Commented Nov 24, 2013 at 21:31
Added the Array into an Object which was suggested below and it worked, I'll include a fiddle next time though. — McDan Garrett
– McDan Garrett, Commented Nov 24, 2013 at 21:35

jfriend00 · Accepted Answer · 2013-11-24 21:29:03Z

1

I'm guessing your question is that you have a string that you retrieved from an attribute and you want to access a variable in your javascript with that name. That is generally done by using the object[varName] where varName is a javascript variable and this lets you access a property on an object of the name help in that variable.

If the variable you want to access is a global variable, then you can access it via string by indexing off the window object because all global variables are properties of the window object:

var currentCat = $(this).attr("array");
var item = window[currentCat][0];

If the variable you want to access is not a global variable, then you need to make it a property on some known object so you can use this same technique.

var myObject = {};
myObject.leads = [];
myObject.leads[0] = "Test 1";
myObject.leads[1] = "Test 2";
myObject.leads[2] = "Test 3";

var currentCat = $(this).attr("array");
var item = myObject[currentCat][0];

FYI, the recommend way to store custom attributes in your HTML is to prefix the custom property with "data-" and then you can use jQuery's .data() to retrieve the custom attribute and you will also be compatible with the HTML5 specification for custom attributes.

<div data-array="leads">

var currentCat = $(this).data("array");

edited Nov 24, 2013 at 21:29

answered Nov 24, 2013 at 21:22

jfriend00

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1 Comment

McDan Garrett Over a year ago

This worked. Thank's so much. I'm now storing my array in an object and I can access it easily! I am also now using the data-array, thanks for the tip!

Kevin Ji · Accepted Answer · 2013-11-24 21:21:26Z

1

It looks like you want to store an array as one of your element's attributes. I recommend that you use .data() instead of attributes to read and write your array values. This prevents you from adding superfluous attributes, and allows you to retrieve your data with the right type.

To store an array (where $ele refers to your jQuery element):

var array = [];
array[0] = "Test";
array[1] = "Test";
$ele.data("array", array);

To retrieve the array:

var array = $ele.data("array");

If you store your array as a data-array attribute of your element, the .data() call above works exactly the same.

answered Nov 24, 2013 at 21:21

Kevin Ji

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