How to deep copy JavaScript objects using structuredClone

The modern way to deep copy a JavaScript variable

For years and years we’ve had to use weird workarounds to do a deep clone of a JavaScript object.

Many of those were bug prone.

Like doing JSON.parse(JSON.stringify(obj)) where some types are be ignored.

Or worse, copying object properties by reference, introducing bugs down the road.

Today we have structuredClone() and it’s part of the DOM API.

It’s not part of JavaScript, it’s a DOM API.

It’s available in recent versions of all modern browsers:

It’s also available in Node.js 17+.