var deepcopy = require('deepcopy');

var data, shallow, deep;

data = {
  objects: {
    array: [
      null, undefined, new Date, /deepcopy/ig
    ],
    object: {
      number: NaN,
      string: 'A',
      boolean: true
    },
    to: null
  }
};

// circular reference
data.objects.to = data;

// shallow copy and deep copy
shallow = data;
deep = deepcopy(data);

// remove entry
delete data.objects;

// results
console.log(data);
// {}
console.log(shallow);
// {}
console.log(require('util').inspect(deep, { depth: null }));
// { objects:
//    { array:
//       [ null,
//         undefined,
//         Sat Jan 10 2015 03:18:32 GMT+0900 (JST),
//         /deepcopy/gi ],
//      object: { number: NaN, string: 'A', boolean: true },
//      to: [Circular] } }

var data, deep;

data = { object: {} };
data.object[Symbol.for('sym')] = 123;

deep = deepcopy(data);

delete data.object;

console.log(data.object);
// undefined
console.log(deep.object[Symbol.for('sym')]);
// 123