Unrecognised export keyword in JSLIGO

Given the following contract:

let foo = (u : unit) : unit => {
        return u
   }

let main = ([parameter, storage] : [list<string>, int]) : [list<operation>, int] => {
   return [list([]) as list<operation>, storage]
}

If I want to test it with a Test.originate I should export the main.

let foo = (u : unit) : unit => {
        return u
   }

export let main = ([parameter, storage] : [list<string>, int]) : [list<operation>, int] => {
   return [list([]) as list<operation>, storage]
}

The compiler refuses it with the following message:

➤ ~/bin/ligo compile contract contract.jsligo                                                                                          
File "contract.jsligo", line 5, characters 0-6:
Ill-formed top-level statement.
At this point, if the statement is complete, one of the following is
expected:
  * a semicolon ';' followed by another statement;
  * a semicolon ';' followed by the end of file;
  * the end of the file.

Therefore if I add a ; at the end of the definition of foo, it compiles correctly.

let foo = (u : unit) : unit => {
        return u
   };

export let main = ([parameter, storage] : [list<string>, int]) : [list<operation>, int] => {
   return [list([]) as list<operation>, storage]
}