Get unique results from JSON array using jQuery

Question

I have this block of code that displays the "categories" from my array into a JQuery simple list.

It works fine, but if there are 3 items from the category "basketball", the category will appear 3 times.

How could I make it so they only appear once ? Thank you.

Here's the code :

function loadCategories() {
    console.debug('About to refresh with sort type : ' + sortType);
    var items = [];

    $.each(catalog.products,
        function(index, value) {
            items.push('<li id="' + index + '">' +
                  '<a data-identity="productId"  href="./productList.page?category=' + value.category + '" >' +
                  '<p style="margin-bottom:0px;margin-top:0px;">' + value.category + '</p></a> </li>');
        }
    );

    categoryView.html(items.join(''));
    categoryView.listview('refresh');
}

Here's the code for my array :

var catalog = {"products": [
{"id": "10001",
"name": "Mountain bike",   
"color": "Grey/Black",
"long-desc": "12-speed, carbon mountain bike.",
"description": "",
"size": "20 inches",
"category": "Outdoors/ Equipment rental",
"sport": "Cycling",
"brand": "DaVinci",
"top-seller": ""},

{"id": "10002",
"name": "Pro Multi Basketball",   
"color": "Rainbow",
"long-desc": "On sale this week only! This limited edition basketball is multi-coloured, and offers pro performance. Fun and games on the court!",
"description": "Limited edition basketball.",
"size": "N/A",
"category": "Team gear",
"sport": "Basketball",
"brand": "Nike",
"top-seller": "x"},

Answer 1

I don't know how your products array is built up (so my example might need some modification according to your needs), but you could write a little piece of code that will first collect your unique categories into a new array:

var categories = [];

$.each(catalog.products, function(index, value) {
    if ($.inArray(value.category, categories) === -1) {
        categories.push(value.category);
    }
});

jsFiddle Demo

categories will hold the unique categories you need, you can use it to build your HTML from that (be careful with the IDs of those li elements though, remember that IDs cannot be duplicate, you might give them a little prefix).