Unfortunately they pretty much dumped the class syntax early on in Vue 3's development, so you'll probably find it quite hard to transition to Vue 3 if you Vue

Unfortunately they pretty much dumped the class syntax early on in Vue 3's development, so you'll probably find it quite hard to transition to Vue 3 if you Vue 2 codebase is full on class components. I had a similar issue having adopted the class syntax and I think rewriting is probably the only way out.