!Object

Object iterate
Object clone
Is object empty?

Clone

// #### JSON clone. If you don`t have a methods.
var cloneOfA = JSON.parse(JSON.stringify(a));


// #### Jquery
// Shallow clone
var newObject = jQuery.extend({}, oldObject);

// Deep clone
var newObject = jQuery.extend(true, {}, oldObject);


// #### Deep clone
Object.clone = function clone(o, copyProto, copyNested){
   function Create(i){
        for(i in o){
          if(o.hasOwnProperty(i)) this[i] = ( copyNested && typeof o[i] == "object" ) 
             ? clone(o[i], true, true) : o[i];
        }
   }
   if(copyProto && "__proto__" in o) Create.prototype = o.__proto__; //IE buggy
   return new Create();
}

//o - target object
//copyProto - if we need to copy prototype
//copyNested - if we need to copy nested objects

var target = {
  "A" : {
       "Z" : 1,
       "X" : 2,
       "Y" : {
          "F" : 3,
          "G" : 4
       }
  }
};

target.__proto__.f = function(){};

var clone1 = Object.clone(target, false, true);
clone1.f //undefined
clone1.A == target.A //false

var clone2 = Object.clone(target, true);
clone2.f //function
clone2.A == target.A //true

Is object empty

// works fine in most browsers
if (Object.keys(obj).length == 0) {
    console.log('empty');
}

// stable
function isEmptyObject(obj) {
    for (var i in obj) {
        if (obj.hasOwnProperty(i)) {
            return false;
        }
    }
    return true;
}

// jquery
if ($.isEmptyObject({});) {
     console.log('empty');
}

Iterate

### by recursion

function recursive(obj) {
    for(let key in obj) {
        if(typeof obj[key] === 'object') {
            recursive(obj[key])
        } else {
            // do something with obj[key]
        }
    }
}