Question

I am looking for group by to perform at second level JSON string. For example i am using the below code to use group by it works pefrectly fine where there is 1 level of array inside JSON string.

Array.prototype.groupBy = function(keyName) {
  var res = {};
  this.forEach(function(x) {
    var k = x[keyName];
    var v = res[k];
    if (!v) v = res[k] = [];
    v.push(x);
  });
  return res;
};

var myObject = {
      "groups": [{
            "id": "2",
            "name": "test group 1",
            "category": "clinical note",
            "author": "RRP"
        }, {
            "id": "1",
            "name": "test group 2",
            "category": "clinical image",
            "author": "LKP"
        }, {
            "id": "2",
            "name": "test group 1",
            "category": "clinical document",
            "author": "RRP"
        }, {
            "id": "4",
            "name": "test group 4",
            "category": "clinical note",
            "author": "John"
        }]

}

myObject.groups.sort(function(a,b) { return a.author > b.author } );    

var byJob = myObject.groups.groupBy('id');

for (var author in byJob) {
  document.write('<h3>'+author+','+byJob[author].length+'</h3>');  
  byJob[author].forEach(function(e) {  
    document.write('<p>'+e.id +', '+e.name+'</p>');
  });

Output::

1,1

1, test group 2

2,2

2, test group 1

2, test group 1

4,1

4, test group 4

Now the above example works perfectly fine but i am looking for second level array grouping in JSON string. For a example if i have following JSON string::

{
    "Category": {
        "old_modi":1,
        "new_modi":1,
        "FORM": [{
            "name":"form1",
            "date":"08/08/2012",
            "location":"abc",
            "PERSON":[{
                "ID":1,
                "author":"xyz"
            }]
        }]
    }
}

Would expect output (Author name would be group by its form name,date and location) ::

xyz
  form1 08/08/2012 xyz

Anybody have any idea which portion of the working copy which i posted in top need to change?

Thanks in advance..

Answer 1

You can iterate through the javascript object recursively. One tricky thing is the javascript object can either be a json object or an array. In my sample solution, I had two different for-loop defined for each of them, there might be a easy way to do that. Anyway, my solution works for any level of groupby. here is the jsFiddle