em_merge_deep_clone.js

var mergeItem = function(item){
    if(Em.typeOf(item) === 'object') { 
      item = merge({}, item); 
    } else if(Em.typeOf(item) === 'array') {
      item = mergeArray(item);
    }
    return item;    
};
 
var mergeArray = function(arr) {
  var i, newArray = [],
      len = arr.length;
    
    for(i=0; i<len; ++i) {
       var value = mergeItem(arr[i]);
       newArray.push(value);
    }
    return newArray;
};
 
var merge = Ember.merge = function(original, updates) {
  for (var prop in updates) {
      if (updates.hasOwnProperty(prop)) {
        var value = mergeItem(updates[prop]);
        original[prop] = value;
      }
  }
  return original;
};
 
 
//Example
var job = {
    name: 'emberjs', 
    firstLevel: {
        name: 'levelOne',
        levelOneArray: [1,2,3],
        secondLevel: {
            secondLevelArray: [{name: 'one'}, {name: 'two'}]                
        }
    }
};
 
 
var job1 = Em.merge({oldName: 'sproutcore'}, job);
 
job1.firstLevel.levelOneArray[0] = 5;
job1.firstLevel.secondLevel.secondLevelArray[0].name = 'changed';
    
console.log(job.firstLevel.levelOneArray[0], job1.firstLevel.levelOneArray[0]); // 1,5
console.log(job.firstLevel.secondLevel.secondLevelArray[0].name, job1.firstLevel.secondLevel.secondLevelArray[0].name); //'one', "changed"