How to Deep clone in javascript

Question

How do you deep clone a JavaScript object?

I know there are various functions based on frameworks like JSON.parse(JSON.stringify(o)) and $.extend(t

Answer 1

The JSON.parse(JSON.stringify()) combination to deep copy Javascript objects is an ineffective hack, as it was meant for JSON data. It does not support values of undefined or function () {}, and will simply ignore them (or null them) when "stringifying" (marshalling) the Javascript object into JSON.

A better solution is to use a deep copy function. The function below deep copies objects, and does not require a 3rd party library (jQuery, LoDash, etc).

function copy(aObject) {
  if (!aObject) {
    return aObject;
  }

  let v;
  let bObject = Array.isArray(aObject) ? [] : {};
  for (const k in aObject) {
    v = aObject[k];
    bObject[k] = (typeof v === "object") ? copy(v) : v;
  }

  return bObject;
}