gistfile1.txt

function merge(obj1, obj2){
    var mergedObj = {}, subHash = {};
    for(key in obj1){
      mergedObj[key] = obj1[key];
    }
    for(key in obj2){ // iterate through level1 keys of obj2
      if(!mergedObj.hasOwnProperty(key)){
        mergedObj[key] = obj2[key]; // if key of obj2 does not exist, add to mergedObj
      } else {
      	subHash = mergedObj[key];
      	if(obj2[key].constructor == Array){
            mergedObj[key] = obj2[key];
        } else {
            for(key2 in obj2[key]){ // iterate through level2 keys of obj2
                subHash[key2] = obj2[key][key2];
            }
            mergedObj[key] = subHash;
      	}
      }	
    }
    return mergedObj;
}

var mergeResult = merge( 
  { 
       name: 'Mickey Mouse', 
       created: 1928, 
       gender: 'Male', 
       friends: [ 'Minnie Mouse', 'Donald Duck', 'Goofy' ],
       appearances: {
           'Steamboat Willie': 1928,
           'The Band Concert': 1935,
           'Brave Little Tailor': 1938
       },
       age: function() {
           return new Date().getFullYear() - this.created;
       }
   },
  {
       ears: true,
       friends: [ 'Minnie' ],
       appearances: {
           'Fantasia': 1940
       }
   }
);

console.log("mergeResult is " , mergeResult);