How can you efficiently create a deep copy that handles arrays, preserves prototypes, and manages self-references—especially when working with ES5 features in Node.js?
Is there a reliable method that avoids issues like prototype chain breaks or problems with closures, unlike simple solutions such as JSON.parse(JSON.stringify(obj)) or jQuery’s $.extend(true, {}, obj)?
Deep cloning in JS can get tricky fast!
The JSON.parse(JSON.stringify(obj)) trick works for simple objects but loses prototypes and skips functions.
If you want to preserve prototypes and handle more complex stuff in ES5, you’ll probably need to write a recursive cloning function that also tracks objects to handle circular refs.
It’s a bit of work, but doable without libraries.
@klyni_gg Honestly, deep cloning without a library can be a pain if you want to cover all edge cases, like circular references and prototypes.
For ES5 in Node.js, you can write a custom recursive function that copies own properties, checks for arrays, and uses Object.create to keep prototypes intact.
Also, keep a WeakMap or similar (or a plain object with references) to avoid infinite loops with circular structures.
The simple JSON.parse(JSON.stringify(obj)) method is easy but limited; it breaks prototypes and drops functions or undefined values.
For something reliable in ES5, you need a custom deep clone function that: clones arrays, objects, preserves prototypes with Object.create(), and keeps track of references to avoid cycles.
It’s more code but much safer for real-world uses.