Deep Copies of Objects in JS

26 Jan 2018

So you wanna copy objects in JS. Great me too. Want them to be not referenced to each other? Yep. Here too.

So go read this.

Done? Sweet.

Well if you’re like me, a little naive I suppose, but never the less I thought I knew.

Object.assign({}, someOtherObject)

Thats supposed to be a reliable method to clone objects…

Until I read that post and realized shit, have I fucked it up.

Well kinda yes maybe and kinda no maybe.

So if you check out what happens if you modify a nested array then yes, PBR - not the beer - but pass by reference holds true.

However…and this was a ok phew what I just wrote will actually be ok.

What happens if the someOtherObject.someKey is deleted? Well then we are still ok, that PBR jumps ship on the deleted one and hangs on for dear life in the newly cloned Object.

Simple, but I needed to see it for myself to be sure.

However truth holds when you try and delete a nested object.

Good to know.