Building Menu from JSON

This post illustrates how to build a Menu from JSON data. The data object below contains an array of objects, each containing “id”, “parentid”, and “text” members. The “text” member is the menu item’s text, the id and parentid members specify the hierarchical structure.

var data = [
{
    "text": "Chocolate Beverage",
    "id": "1",
    "parentid": "-1"
}, {
    "id": "2",
    "parentid": "1",
    "text": "Hot Chocolate"
}, {
    "id": "3",
    "parentid": "1",
    "text": "Peppermint Hot Chocolate"
}, {
    "id": "4",
    "parentid": "1",
    "text": "Salted Caramel Hot Chocolate"
}, {
    "id": "5",
    "parentid": "1",
    "text": "White Hot Chocolate"
}, {
    "id": "6",
    "text": "Espresso Beverage",
    "parentid": "-1"
}, {
    "id": "7",
    "parentid": "6",
    "text": "Caffe Americano"
}, {
    "id": "8",
    "text": "Caffe Latte",
    "parentid": "6"
}, {
    "id": "9",
    "text": "Caffe Mocha",
    "parentid": "6"
}, {
    "id": "10",
    "text": "Cappuccino",
    "parentid": "6"
}, {
    "id": "11",
    "text": "Pumpkin Spice Latte",
    "parentid": "6"
}, {
    "id": "12",
    "text": "Frappuccino",
    "parentid": "-1"
}, {
    "id": "13",
    "text": "Caffe Vanilla Frappuccino",
    "parentid": "12"
}, {
    "id": "15",
    "text": "450 calories",
    "parentid": "13"
}, {
    "id": "16",
    "text": "16g fat",
    "parentid": "13"
}, {
    "id": "17",
    "text": "13g protein",
    "parentid": "13"
}, {
    "id": "14",
    "text": "Caffe Vanilla Frappuccino Light",
    "parentid": "12"
}]

As a first step, we will create a function that builds the hierarchical structure. The builddata function below iterates through the data and creates the source object. The sub items of each item are added to its “items” member. The item’s text is stored in a “label” member.

var builddata = function () {
    var source = [];
    var items = [];
    // build hierarchical source.
    for (i = 0; i < data.length; i++) {
        var item = data[i];
        var label = item["text"];
        var parentid = item["parentid"];
        var id = item["id"];

        if (items[parentid]) {
            var item = { parentid: parentid, label: label, item: item };
            if (!items[parentid].items) {
                items[parentid].items = [];
            }
            items[parentid].items[items[parentid].items.length] = item;
            items[id] = item;
        }
        else {
            items[id] = { parentid: parentid, label: label, item: item };
            source[id] = items[id];
        }
    }
    return source;
}
var source = builddata();

The next step is to create a recursive function that traverses the source object and dynamically appends UL and LI elements.

var buildUL = function (parent, items) {
    $.each(items, function () {
        if (this.label) {
            // create LI element and append it to the parent element.
            var li = $("<li>" + this.label + "</li>");
            li.appendTo(parent);
            // if there are sub items, call the buildUL function.
            if (this.items && this.items.length > 0) {
                var ul = $("<ul></ul>");
                ul.appendTo(li);
                buildUL(ul, this.items);
            }
        }
    });
}
var ul = $("<ul></ul>");
ul.appendTo("#jqxMenu");
buildUL(ul, source);

After that, we use the script below to create the Menu:

$("#jqxMenu").jqxMenu({ width: '600', height: '30px'});

Finally, we add a DIV element with id=’jqxMenu’ to the document’s body:

<div id='jqxMenu'>
</div>

You can also build a Tree from the above code. In order to achieve that, you need to use the jqxTree constructor.

$("#jqxMenu").jqxTree({ width: '300', height: '300px'});

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