I don't want to be too harsh on the Svelte author. It's a minor inconvenience.
The guy did some incredible work - he wrote all of this code in a week. I'll look at the REPL code to see if there's a simple fix. All the levels of indirection, code generation and bundling may take a while for my non-Rich-Harris brain to sort out.
Why not transpile the Svelte compiler to ES5 so it will run on all browsers? Otherwise devs may get the impression Svelte generated applications will not work on all browsers.
The guy did some incredible work - he wrote all of this code in a week. I'll look at the REPL code to see if there's a simple fix. All the levels of indirection, code generation and bundling may take a while for my non-Rich-Harris brain to sort out.