Which is the best method for deep cloning in JavaScript?

Similarly, cloning things like getters means you're potentially copying over closures, which means your new cloned object now has references to its source and interacting with it may mutate the source. This is a pretty serious hazard that (IMO) justifies not cloning getters/setters, at least by default.

Cloning freeze/seal status would also lower the usability of your cloning API, because now if you wanted to make a non-frozen copy of a frozen object, you can't use the clone API.

But one thing not included in this page is that there are things it just doesn't serialize, even when it's actual data:

  const native = { number: Number.POSITIVE_INFINITY };

  const cloned = JSON.parse(JSON.stringify(native));


  // unlike NaN, we can compare Number.POSITIVE_INFINITY to itself
  console.log(native.number === native.number);

  // but it doesn't serialize
  console.log(native.number === cloned.number);

  console.log(cloned);

  true
  false
  {number: null}

"cloneJSON is very slow and can’t do much. Please avoid it."

I mean, I also use it since forever.

But I might look into the winner cloneLib.

If it is really faster, it might be worth it, but I likely still won't trust it for anything complex.