How do I run JavaScript on CodePen?

You can import React (any pretty much any other npm package) from Skypack like this: import React from “https://cdn.skypack.dev/[email protected]”; CodePen will help you fix imports like that automatically. You’ll see an icon like this come up, which you click to open and are offered a button to click to fix the issue.

Simply drag-and-drop CSS, JS, or preprocessor versions of those files onto the Assets area and they will upload . Then click the file name to get the URL and copy-and-paste it into external resources.

How to run code in CodePen