Learn the difference between shallow and deep copying in JavaScript, and the best way to deep copy an object in JavaScript.

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In a reassignment operation involving primitive data types such as strings, numbers and booleans, the original variable is copied by JavaScript. With non-primitive data types like arrays and objects, only a reference to the values is passed. This is also known as shallow copying. If we instead want to copy an object so that we can modify it without affecting the original object, we need to make a deep copy.

The Best Way to Deep Copy an Object in JavaScript

5 Ways To Deep Copy Objects in JavaScript

<p>There is built-in support for <a href="https://developer.mozilla.org/en-US/docs/Web/API/structuredClone" target="_blank" rel="noopener nofollow">deep cloning</a> an object. I think it was introduced recently, looking at the last update from the docs itself.</p>


<p>I implemented a “lazy” copy thing a while back using proxies. It’s kinda similar to what Immer does.
…Tbh, I’d probably just recommend Immer now if something like that is needed.</p>
