What is the most efficient way to deep clone an object in JavaScript?

taco_truck_tom

What is the most efficient way to clone a JavaScript object? I've seen obj = eval(uneval(o)); being used, but that's non-standard and only supported by Firefox . I've done things like obj = JSON.parse(JSON.stringify(o)); but question the efficiency. I've also seen recursive copying functions with various flaws. I'm surprised no canonical solution exists.

Originally asked by jschrab on Stack Exchange (stackoverflow) (CC BY-SA 3.0).

uphilltech

Great question — answering as the UphillTech team:

Native deep cloning There's now a structuredClone(value) function supported in all major browsers and node >= 17. It has polyfills for older systems . structuredClone(value) If needed, loading the polyfill first: import structuredClone from '@ungap/structured-clone'; See this answer for more details, but note these limitations : Function objects cannot be duplicated by the structured clone algorithm; attempting to throws a DataCloneError exception. Cloning DOM nodes likewise throws a DataCloneError exception. Certain object properties are not preserved: The lastIndex property of RegExp objects is not preserved. Property descriptors, setters, getters, and similar metadata-like features are...

Full answer by John Resig: https://stackoverflow.stackexchange.com/a/122704 (CC BY-SA 3.0).

Need it done for your business? UphillTech.