Status: refused by design
throw 1; export default 2; is not FunctionalScript. A throw before or after a module's exports is valid JavaScript, and fjs compile refuses it by design: the demo below shows what it prints.
A module is a function (module structure), and a body ends in return or in throw, not in both. So a module's throw stands where its export default would, in place of it: after its imports and every const, and with nothing after it. JavaScript runs the statements in order, so throw 1; export default 2; fails at every load, and the export after it is one no importer can read.
The row mod.throw-position of refused constructs registers the refusal, and module structure gives its reason.
throw 1;
export default 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: none, since importing it throws 1.
Keep one ending: the export, as alternative.f.js does, or the throw alone, for a module meant to fail.
export default 2;
It answers 2.
Today fjs compile prints unexpected token at the export. 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.