How to create a copy of anything in Javascript?

Modern Javascript developers are used to the following syntax to create a copy of an object:

let copy = {...object};Code language: JavaScript (javascript)

While this approach works fine, it creates a shallow copy of the object, not a fully-fledged clone that also duplicates nested objects and arrays.

As a result, Javascript developers have learned another trick to perform a deep copy:

let copy = JSON.parse(JSON.stringify(object));Code language: JavaScript (javascript)

The idea of this approach is to turn an object into a JSON string before parsing that string back into a brand-new object. It works, but it’s not elegant and looks like a hack.

As a result, a better approach has been added to the Javascript language: the structuredClone function. It’s a syntax improvement that creates deep clones efficiently:

let copy = structuredClone(object);Code language: JavaScript (javascript)

The function is supported across all recent major browsers as shown on Can I use:

If you need to support another browser, there is a polyfill implementation in core.js.