Can any valid Wolfram code or Mathematica expression run well on WLJS Notebook? The answer is yes*, but the devil is in the details.

Static output and anything related to computation is 100% transferable. You can take pretty much any code from Stack Exchange or Wolfram Community and it should work out of the box with a high chance, since we use the same Wolfram Language kernel, in the form of the freeware Wolfram Engine distribution. Manipulate and Animate are compatible too - and fully interactive!

However, low-level dynamics do need to be ported to execute correctly.

Here's a guide on how to port (if actually needed) a program from Wolfram Mathematica to WLJS: https://wljs.io/frontend/Guides/Migration

Any .nb (Mathematica Notebook) is, in principle, automatically converted with some compromises, of course. We're still improving this! Hope this guide helps you, or your LLM buddy 🙂