javascript - how to transform/group this kind of raw json data into hierarchy strucutre -

i have set of room data in json, each room data includes site, building , floor resides in.

the data examples like

[ {   'site':'liverpool', 'building':'building a', 'floor':'0', 'room':'room a' }, {   'site':'liverpool', 'building':'building a', 'floor':'1', 'room':'room b'  }, {   'site':'liverpool', 'building':'building b', 'floor':'0', 'room':'room a'  } ............ ] 

now using javascript break down data set hierarchy structure, such as

{     'site':[         {             'name':'liverpool',             'buildings':[                 {                     'name':'building a',                     'floors':[                      {                          'name':0,                          'rooms':['room a', 'room b']                      }                     ]                 }             ]         }     ] }  

for me, still hard transform raw data wanted structure, instruct me how it?

i have tried underscore, achieved 1 hierarchy.

 var groups = _.groupby(data,function(room){                 return (room.site+","+room.building+","+room.floor);                     })  

assuming var data json:

var sites = [];  for(var i=0,l=data.length;i<l;i++) {     var row = data[i];     var site = false;     var building = false;     var floor = false;  //  search existing site     for(var j=0,k=sites.length;j<k;j++) {         if(sites[j].name == row.site) {             site = j;             break;         }     }      if(site === false) {         site = sites.length;         sites[site] = {             name: row.site,             buildings: []         };     }  //  search existing building     for(var j=0,k=sites[site].buildings.length;j<k;j++) {         if(sites[site].buildings[j].name == row.building) {             building = j;             break;         }     }      if(building === false) {         building = sites[site].buildings.length;         sites[site].buildings[building] = {             name: row.building,             floors: []         };     }  //  search existing floor     for(var j=0,k=sites[site].buildings[building].floors.length;j<k;j++) {         if(sites[site].buildings[building].floors[j] == row.floor) {             floor = j;             break;         }     }      if(floor === false) {         floor = sites[site].buildings[building].floors.length;         sites[site].buildings[building].floors[floor] = row.floor;     } } 

resulting structure:

var sites = [     {         "name":"liverpool",         "buildings":[             {                 "name":"building a",                 "floors":[                     "0",                     "1"                 ]             },             {                 "name":"building b",                 "floors":[                     "0"                 ]             }         ]     } ]; 

use it:

var liverpool = sites[0]; var building_b = liverpool.buildings[1]; 

there better ways of doing though.