Re-Structuring a JSON

Question

OK guys need some help out there. I\'m still learning Javascript and its interactions JSON. I have a a JSON like this

[{
  \"categories\":\"Food\",
  \"subca         


        

Answer 1

I workout a solution, but I'm not sure how it will handle big json data. Assume that the json var stores your data:

categories = [];
json.forEach(function(entry) {  
    var cindex = categories.map(function(category) { 
        return category.name; 
    }).indexOf(entry.categories);

    if (cindex < 0) {
        // Not found in categories array
        cindex = categories.push({
            name: entry.categories,
            subcategories: []
        }) - 1; // -1 to fix the index
    }

    // Lets search the subcategory
    var category = categories[cindex];

    var sindex = category.subcategories.map(
        function(subcategory) {
            return subcategory.name;
        }
    ).indexOf(entry.subcategories);

    if (sindex < 0) {
      // Not Found
        sindex = category.subcategories.push({
            name: entry.subcategories,
            items: []
        }) - 1; 
    } 
    // Subcategory exists. Just push
    category.subcategories[sindex].items.push({
        pid: entry.pid,        
        description: entry.description,
        title: entry.title
    });
});

var menu = {
    menu: {
        categories: categories
    }
};

Working Fiddle

Answer 2

I gave this a shot and might as well post my results. The data doesn't line up perfectly with what you have. It doesn't require jQuery, and it can be used to sort data multiple times.

Object.prototype.groupBy = function(itemName, preGrouped)
{
    if(preGrouped)
    {
        for(prop in this)
        {
            if(typeof(this[prop]) === 'object' && this[prop].groupBy !== undefined)
            {
                var reGroup = this[prop].groupBy(itemName);  
                this[prop] = reGroup;
            }
        }
        return this;
    }
    else
    {
        var uniqueItems = {};
        var uniqueItemLength = 0;
        for(var i=0, length=this.length; i < length; i++)
        {
           var item = this[i]; 
           var z =0;
           var found = false;
           while(z < uniqueItemLength)
           {     
               if(item[itemName] in uniqueItems)
               {
                   uniqueItems[item[itemName]].push(item);
                   found = true;
                   break;
               }
               z++;
           }
            if(!found)
            {
                uniqueItems[item[itemName]] = [];
                uniqueItems[item[itemName]].push(item); 
                uniqueItemLength++;
            }      
        }
        return uniqueItems;
    } 
}

It gets called by:

var convertedData = oldJSON.groupBy('categories').groupBy('subcategories', true)

Beterraba's answer is correct. I put some time in this one and figured I'd at least post. Maybe it would help someone else.

http://jsfiddle.net/8VRuy/