How to join JSON db's on a key like in sqlite?

I am trying to join 2 json database on a key, like you would in sqlite, using 2 for loops.

var med_conditions = require('ui/common/med/med_databases/conditions').test;
     var med_bridge = require('ui/common/med/med_databases/med_bridge').test;
 
     var med_list = [];
 
     for (var i = 0; i < med_bridge.length; i++) {
 
          if (med_bridge[i].z_parent_id == args.title_id) {
               med_list.push(med_bridge[i]);
          }
 
     };

var med_title =[];
 
     for (var i = 0; i < med_conditions.length; i++) {
         if (med_list[i].z_condition_map_id_2 == med_conditions.z_condition_map_id_2) {
 
               med_title.push(med_conditions[i]);
 
         }
 
     };
 
 
     var data = [];
 
     for (var i = 0; i < med_title.length; i++) {
          data.push({
               properties : {
                    title : med_title[i].z_condition,
                    searchableText : med_title[i].z_condition
               }
          });
     }
     listSection.setItems(data);