Javascript passing by copy of reference, a simple test across closure.

gistfile1.js

var CL = function(){
   config = {
      field: {
         key: []
      }
   },
   add_val = function(val) {
      config.field.key.push(val)
   }
   return {
      get_key : function() {
         return config.field.key
      },
      add_val: add_val,
      list_vals: function() {
         return config.field.key
      }
   }
}

cl = CL()
srvr = cl.get_key()
srvr.push('#1')
cl.add_val('#2')
console.log(srvr)
console.log(cl.list_vals())