Skip to content

How to clone anything in JavaScript

We used to do all sorts of stuff in JavaScript land in regards to cloning.

Why?

Because ..references.

Primitive types (strings, numbers, booleans..) are always correctly “cloned” because they are passed by value.

Everything else (objects, arrays, dates, whatever) is an object. And objects are passed by reference.

So we had to do deep cloning using various ways otherwise you end up with the same object reference, under a different name.

But it’s 2023 and we can use structuredClone().

const b = structuredClone(a)

This also deeply clones non-primitive types.

Just pay attention it’s a recent API, so if you use it in the browser make sure you use a build tool that provides core-js (babel) polyfills.


→ Get my JavaScript Beginner's Handbook

I wrote 21 books to help you become a better developer:

  • HTML Handbook
  • Next.js Pages Router Handbook
  • Alpine.js Handbook
  • HTMX Handbook
  • TypeScript Handbook
  • React Handbook
  • SQL Handbook
  • Git Cheat Sheet
  • Laravel Handbook
  • Express Handbook
  • Swift Handbook
  • Go Handbook
  • PHP Handbook
  • Python Handbook
  • Linux Commands Handbook
  • C Handbook
  • JavaScript Handbook
  • Svelte Handbook
  • CSS Handbook
  • Node.js Handbook
  • Vue Handbook
...download them all now!

Related posts that talk about js: