Deep clone object in Javascript except Object.assign [duplicate]

Question

Object.assign doesn't deep copy an object. considering following code it should print 0 0 0 1 but it is printing 0 0 1 1.

var obj = {
  "value": {
    "default": 0
  }
};
var newo = Object.assign({}, obj);

console.log(obj.value.default);
console.log(newo.value.default);

newo.value.default = 1;

console.log(obj.value.default);
console.log(newo.value.default);

I know we can use JSON.parse(JSON.stringify(obj)). but is that a best practice solution?