Question

I have a xml file like this: (this is dynamically create xml file the categories are not static)

<data>
    <step id="1">
        <category id="js"></category>
        <category id="css"></category>
        <category id="xml"></category>
    </step>
    <step id="2">
        <category id="js"></category>
        <category id="css"></category>
        <category id="xml"></category>
        <category id="php"></category>
        <category id="html"></category>
    </step>
    <step id="3">
        <category id="xml"></category>
        <category id="php"></category>
        <category id="html"></category>
    </step>
</data>

I want convert the xml file in a javascript object i do it with jquery

$.get('data.xml', function(xml){
    var oXML = $(xml).find('data'),
        data = {};

    oXML.each(function(){
        var stepID = jQuery(this).attr('id');
        data[stepID] = {};

        jQuery(this).each(function(){
            var categoryID = jQuery(this).attr('id')
            data[stepID][categoryID] = 'is available';

        });
    });
});

the result looks like this

obj = {
1: {
    js: 'is available',
    css: 'is available',
    xml: 'is available'
},

2: {
    js: 'is available',
    css: 'is available',
    xml: 'is available',
    php: 'is available',
    html: 'is available'

},

3: {
    xml: 'is available',
    php: 'is available',
    html: 'is available'
}
}

but i want have all categories in all steps. do you have a idea how i can do it?
I want a result object like this

obj = {
    1: {
        js: 'is available',
        css: 'is available',
        xml: 'is available',
        php: 'is not available',
        html: 'is not available'
    },

    2: {
        js: 'is available',
        css: 'is available',
        xml: 'is available',
        php: 'is available',
        html: 'is available'

    },

    3: {
        js: 'is not available',
        css: 'is not available',
        xml: 'is available',
        php: 'is available',
        html: 'is available'
    }
}

Answer 1

collect all categories and then enumerate through data and set missing categories:

$.get('data.xml', function(xml){
    var oXML = $(xml).find('data'),
        data = {},
        categories = {};

    oXML.each(function(){
        var stepID = jQuery(this).attr('id');
        data[stepID] = {};
        jQuery(this).each(function(){
            var categoryID = jQuery(this).attr('id');
            if (!categories[categoryID]) {
                categories[categoryID] = true;
            }
            data[stepID][categoryID] = 'is available';
        });
    });
    $.each(data, function (key, value) {
        $.each(categories, function (key) {
            if (value[key] === undefined) {
                value[key] = 'is not available';
            }
        });
    });
});