javascript complex recurrsion

Question

Given Below is my data in data array. What i am doing in code below is that from that given data i have to construct json in a special format which i also gave below.

//code start here
 var hierarchy={};
 hierarchy.name="Hierarchy";
 hierarchy.children=[{"name":"","children":[{"name":"","children":[]}]}];
 var countryindex;
 var flagExist=false;
 var data = [
 {country :"America", city:"Kansas", employe:'Jacob'},
 {country :"Pakistan", city:"Lahore", employe:'tahir'},
 {country :"Pakistan", city:"Islamabad", employe:'fakhar'} ,
 {country :"Pakistan", city:"Lahore", employe:'bilal'},
 {country :"India", city:"d", employe:'ali'} ,
 {country :"Pakistan", city:"Karachi", employe:'eden'},
 {country :"America", city:"Kansas", employe:'Jeen'} ,
 {country :"India", city:"Banglore", employe:'PP'} ,
 {country :"India", city:"Banglore", employe:'JJ'} ,
 ];
 for(var i=0;i<data.length;i++)
 {
 for(var j=0;j<hierarchy.children.length;j++)
 {
 //for checking country match
 if(hierarchy.children[j].name==data[i].country)
 {
 countryindex=j;
 flagExist=true;
 break;
 }
 }
 if(flagExist)//country match now no need to add new country just add city in it
 {
 var cityindex;
 var cityflag=false;
 //hierarchy.children[countryindex].children.push({"name":data[i].city,"children":[]})
 //if(hierarchy.children[index].children!=undefined)
 for(var k=0;k< hierarchy.children[countryindex].children.length;k++)
 {
 //for checking city match
 if(hierarchy.children[countryindex].children[k].name==data[i].city)
 {
 // hierarchy.children[countryindex].children[k].children.push({"name":data[i].employe})
 cityflag=true;
 cityindex=k;
 break;
 }
 }
 if(cityflag)//city match now add just empolye at that city index
 {
 hierarchy.children[countryindex].children[cityindex].children.push({"name":data[i].employe});
 cityflag=false;
 }
 else//no city match so add new with employe also as this is new city so its emplye will be 1st
 {
 hierarchy.children[countryindex].children.push({"name":data[i].city,children:[{"name":data[i].employe}]});
 //same as above
 //hierarchy.children[countryindex].children[length-1].children.push({"name":data[i].employe});
 }
 flagExist=false;
 }
 else{ //no country match adding new country //with city also as this is new city of new country
 console.log("sparta");
 hierarchy.children.push({"name":data[i].country,"children":[{"name":data[i].city,"children":[{"name":data[i].employe}]}]});
 // hierarchy.children.children.push({"name":data[i].city,"children":[]});
 }
 //console.log(hierarchy);
 }
 hierarchy.children.shift();
 var j=JSON.stringify(hierarchy);
//code ends here

//here is the json which i seccessfully formed from the code

{
"name":"Hierarchy",
"children":[
{
"name":"America",
"children":[
{
"name":"Kansas",
"children":[{"name":"Jacob"},{"name":"Jeen"}]}]},
{
"name":"Pakistan",
"children":[
{
"name":"Lahore",
"children":
[
{"name":"tahir"},{"name":"bilal"}]},
{
"name":"Islamabad",
"children":[{"name":"fakhar"}]},
{
"name":"Karachi",
"children":[{"name":"eden"}]}]},
{
"name":"India",
"children":
[
{
"name":"d",
"children":
[
{"name":"ali"}]},
{
"name":"Banglore",
"children":[{"name":"PP"},{"name":"JJ"}]}]}]}

Now the orignal problem is that currently i am solving this problem for data of array of three keys and i have to go for 3 nested loops now i want to optimize this solution so that if data array of object has more than 3 key say 5 {country :"America", state:"NewYork",city:"newYOrk",street:"elm", employe:'Jacob'}, or more than my solution will not work and i cannot decide before how many keys will come so i thought recursion may suit best here. But i am horrible in writing recurrsion and the case is also complex. Can some awesome programmer help me writing recurrsion or suggest some other solution.

• CodeChimp: I would suggest trying your hand at a recursive solution, then posting where you have problems with it.

Answer 1

I made a functions that can help you, is recursive and support any length levels, but the code is a bit long

 var data = [
 {country :"America", city:"Kansas", employe:'Jacob'},
 {country :"Pakistan", city:"Lahore", employe:'tahir'},
 {country :"Pakistan", city:"Islamabad", employe:'fakhar'} ,
 {country :"Pakistan", city:"Lahore", employe:'bilal'},
 {country :"India", city:"d", employe:'ali'} ,
 {country :"Pakistan", city:"Karachi", employe:'eden'},
 {country :"America", city:"Kansas", employe:'Jeen'} ,
 {country :"India", city:"Banglore", employe:'PP'} ,
 {country :"India", city:"Banglore", employe:'JJ'} ,
 ];
function groupByLevel( source, levels, config ){
 config = ( typeof config == "object" && config ) || {};
 var internalConfig = {
 keyName: config.keyName || "name",
 collectionName: config.collectionName || "children"
 };
 var hierarchy = {};
 hierarchy[internalConfig.keyName] = "Hierarchy";
 hierarchy[internalConfig.collectionName] = source;
 var sourceArray = [hierarchy];
 for(var i = 0; i < levels.length; i++){
 var newSourceArray = [];
 for(var j = 0; j < sourceArray.length; j++){
 var oldArray = sourceArray[j][internalConfig.collectionName];
 var newArray = groupBy(oldArray, levels[i], internalConfig); 
 sourceArray[j][internalConfig.collectionName] = newArray;
 for(var l = 0; l < newArray.length; l++){
 newSourceArray.push(newArray[l]);
 }
 }
 sourceArray = newSourceArray;
 }
 return hierarchy;
}
function duplicate(obj){
 var newObj = {};
 for(var i in obj) newObj[i] = obj[i];
 return newObj;
}
function objlength(obj){
 var length = 0;
 for(var i in obj) length++;
 return length
}
function groupBy(array, key, config){
 var group = {};
 for(var i = 0; i < array.length; i++){
 var item = array[i];
 var currentKey = item[key]; 
 if( ! group[currentKey] ) group[currentKey] = [];
 var clone = duplicate(item);
 delete clone[key]; 
 if( objlength(clone) ) group[currentKey].push( clone );
 }
 var returnGroup = [];
 for(var i in group){
 var groupItem = {};
 groupItem[config.keyName] = i;
 if( group[i].length ) groupItem[config.collectionName] = group[i];
 returnGroup.push( groupItem );
 }
 return returnGroup;
}
var result = groupByLevel(data, ["country", "city", "employe"] );
var yourJson = JSON.stringify(result);

the functions groupByLevel, groupBy, duplicate and objLength will to process your groupping.

in this link http://jsfiddle.net/Castrolol/2TkkW/ you can see a more level example with you data.

if you want, you can put on a single object to separe and turn reusable.

sorry for my bad english.