Status: refused by design
export default 1; export const is not FunctionalScript. export default 1; export const a = 2; is valid JavaScript, and fjs compile refuses it by design: the demo below shows what it prints.
A module reads in one order: imports first, then constants, then export default, last. JavaScript lets the statements stand in any order; FunctionalScript keeps the one, so a reader finds the module's answer at its end (module structure).
The row mod.export-after-default of refused constructs registers the refusal, and module structure gives its reason.
export default 1;
export const a = 2;
The demo on this page compiles sample.mjs, the module above, with this build's fjs compile, and shows the line it prints and the token it refuses. Below that it shows what JavaScript answers for the same module: 1.
Move export default to the end of the module, as alternative.f.js does:
export const a = 2;
export default 1;
It answers 1.
Today fjs compile prints unexpected token at the refused token. The demo proposes what it should print instead: the reason at the same token, what JavaScript does there, and the allowed spelling, the line alternative.f.js writes, as help. The page compiles the alternative too, so the suggestion is one the compiler accepts.